AD9511/PCB_技术文档

1.2 GHz Clock Distribution IC, PLL Core,

Dividers, Delay Adjust, Five Outputs

AD9511

FEATURES

FUNCTIONAL BLOCK DIAGRAM

VS GND

RSET

CPRSET VCP

Low phase noise phase-locked loop core

Reference input frequencies to 250 MHz

Programmable dual-modulus prescaler

Programmable charge pump (CP) current

Separate CP supply (VCP_S) extends tuning range

Two 1.6 GHz, differential clock inputs

5 programmable dividers, 1 to 32, all integers

Phase select for output-to-output coarse delay adjust

3 independent 1.2 GHz LVPECL outputs

Additive output jitter 225 fs rms

PLL

REF

DISTRIBUTION

REF

AD9511

REFIN

R DIVIDER

N DIVIDER

PHASE

FREQUENCY

DETECTOR

CHARGE

PUMP

REFINB

CP

SYNCB,

RESETB

PDB

FUNCTION

PLL

SETTINGS

STATUS

CLK1

CLK2

CLK2B

CLK1B

PROGRAMMABLE

DIVIDERS AND

PHASE ADJUST

LVPECL

OUT0

/1, /2, /3... /31, /32

OUT0B

2 independent 800 MHz/250 MHz LVDS/CMOS clock outputs

Additive output jitter 275 fs rms

Fine delay adjust on 1 LVDS/CMOS output

Serial control port

OUT1

OUT1B

LVPECL

OUT2

OUT2B

Space-saving 48-lead LFCSP

SCLK

SDIO

SDO

CSB

LVDS/CMOS

SERIAL

CONTROL

PORT

OUT3

OUT3B

APPLICATIONS

OUT4

Δ

T

Low jitter, low phase noise clock distribution

Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs

High performance wireless transceivers

High performance instrumentation

OUT4B

DELAY

ADJUST

Figure 1.

Broadband infrastructure

Each output has a programmable divider that may be bypassed

or set to divide by any integer up to 32. The phase of one clock

output relative to another clock output may be varied by means

of a divider phase select function that serves as a coarse timing

adjustment. One of the LVDS/CMOS outputs features a

programmable delay element with full-scale ranges up to 10 ns

of delay. This fine tuning delay block has 5-bit resolution, giving

32 possible delays from which to choose for each full-scale

setting.

GENERAL DESCRIPTION

The AD9511 provides a multi-output clock distribution

function along with an on-chip PLL core. The design

emphasizes low jitter and phase noise to maximize data

converter performance. Other applications with demanding

phase noise and jitter requirements also benefit from this part.

The PLL section consists of a programmable reference divider

(R); a low noise phase frequency detector (PFD); a precision

charge pump (CP); and a programmable feedback divider (N).

By connecting an external VCXO or VCO to the CLK2/CLK2B

pins, frequencies up to 1.6 GHz may be synchronized to the

input reference.

The AD9511 is ideally suited for data converter clocking

applications where maximum converter performance is

achieved by encode signals with subpicosecond jitter.

The AD9511 is available in a 48-lead LFCSP and can be

operated from a single 3.3 V supply. An external VCO, which

requires an extended voltage range, can be accommodated by

connecting the charge pump supply (VCP) to 5.5 V. The

temperature range is −40°C to +85°C.

There are five independent clock outputs. Three outputs are

LVPECL (1.2 GHz), and two are selectable as either LVDS

(800 MHz) or CMOS (250 MHz) levels.

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable.

However, no responsibility is assumed by Analog Devices for its use, nor for any

infringements of patents or other rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and

registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

Fax: 781.461.3113

www.analog.com

AD9511

TABLE OF CONTENTS

Specifications..................................................................................... 4

A and B Counters................................................................... 30

Determining Values for P, A, B, and R ................................ 30

Phase Frequency Detector (PFD) and Charge Pump ....... 31

Antibacklash Pulse................................................................. 31

STATUS Pin ............................................................................ 31

PLL Digital Lock Detect........................................................ 31

PLL Analog Lock Detect ....................................................... 32

Loss of Reference.................................................................... 32

FUNCTION Pin ......................................................................... 32

RESETB: 58h<6:5> = 00b (Default)..................................... 32

SYNCB: 58h<6:5> = 01b ....................................................... 32

PDB: 58h<6:5> = 11b ............................................................ 33

Distribution Section................................................................... 33

CLK1 and CLK2 Clock Inputs.................................................. 33

Dividers........................................................................................ 33

Setting the Divide Ratio ........................................................ 33

Setting the Duty Cycle........................................................... 33

Divider Phase Offset.............................................................. 37

Delay Block ................................................................................. 38

Calculating the Delay ............................................................ 38

Outputs ........................................................................................ 38

Power-Down Modes .................................................................. 39

Chip Power-Down or Sleep Mode—PDB........................... 39

PLL Power-Down................................................................... 39

Distribution Power-Down .................................................... 39

Individual Clock Output Power-Down............................... 39

Individual Circuit Block Power-Down................................ 39

Reset Modes ................................................................................ 40

PLL Characteristics ...................................................................... 4

Clock Inputs .................................................................................. 5

Clock Outputs............................................................................... 6

Timing Characteristics ................................................................ 7

Clock Output Phase Noise .......................................................... 9

Clock Output Additive Time Jitter........................................... 12

PLL and Distribution Phase Noise and Spurious................... 14

Serial Control Port ..................................................................... 15

FUNCTION Pin ......................................................................... 15

STATUS Pin ................................................................................ 16

Power............................................................................................ 16

Timing Diagrams............................................................................ 17

Absolute Maximum Ratings.......................................................... 18

Thermal Characteristics ............................................................ 18

ESD Caution................................................................................ 18

Pin Configuration and Function Descriptions........................... 19

Terminology .................................................................................... 21

Typical Performance Characteristics ........................................... 22

Typical Modes of Operation.......................................................... 26

PLL with External VCXO/VCO Followed by Clock

Distribution................................................................................. 26

Clock Distribution Only............................................................ 26

PLL with External VCO and Band-Pass Filter Followed by

Clock Distribution...................................................................... 27

Functional Description.................................................................. 29

Overall.......................................................................................... 29

PLL Section ................................................................................. 29

PLL Reference Input—REFIN.............................................. 29

VCO/VCXO Clock Input—CLK2........................................ 29

PLL Reference Divider—R.................................................... 29

VCO/VCXO Feedback Divider—N (P, A, B) ..................... 29

Power-On Reset—Start-Up Conditions when VS

is Applied................................................................................. 40

Asynchronous Reset via the FUNCTION Pin ................... 40

Soft Reset via the Serial Port................................................. 40

Rev. A | Page 2 of 60

AD9511

Single-Chip Synchronization.....................................................40

SYNCB—Hardware SYNC ....................................................40

Soft SYNC—Register 58h<2> ...............................................40

Multichip Synchronization ........................................................40

Serial Control Port ..........................................................................41

Serial Control Port Pin Descriptions........................................41

General Operation of Serial Control Port ...............................41

Framing a Communication Cycle with CSB .......................41

Communication Cycle—Instruction Plus Data..................41

Write .........................................................................................41

Read ..........................................................................................42

The Instruction Word (16 Bits).................................................42

MSB/LSB First Transfers ............................................................42

Register Map and Description.......................................................45

Summary Table............................................................................45

Register Map Description..........................................................47

Power Supply ...................................................................................54

Power Management ....................................................................54

Applications .....................................................................................55

Using the AD9511 Outputs for ADC Clock Applications ....55

CMOS Clock Distribution.........................................................55

LVPECL Clock Distribution......................................................56

LVDS Clock Distribution...........................................................56

Power and Grounding Considerations and Power Supply

Rejection.......................................................................................56

Outline Dimensions........................................................................57

Ordering Guide ...........................................................................57

REVISION HISTORY

Changes to Divider Phase Offset Section ....................................37

Changes to Individual Clock Output Power-Down Section.....39

Changes to Individual Circuit Block Power-Down Section......39

Changes to Soft Reset via the Serial Port Section.......................40

Changes to Multichip Synchronization Section..........................40

Changes to Serial Control Port Section .......................................41

Changes to Serial Control Port Pin Descriptions Section .........41

Changes to General Operation of Serial

6/05—Rev. 0 to Rev. A

Changes to Features ..........................................................................1

Changes to General Description .....................................................1

Changes to Table 1 and Table 2 .......................................................5

Changes to Table 4 ............................................................................7

Changes to Table 5 ............................................................................9

Changes to Table 6 ..........................................................................14

Changes to Table 8 and Table 9 .....................................................15

Changes to Table 11 ........................................................................16

Changes to Table 13 ........................................................................20

Changes to Figure 19 to Figure 23 ................................................24

Changes to Figure 30 and Figure 31 .............................................26

Changes to Figure 32 ......................................................................27

Changes to Figure 33 ......................................................................28

Changes to VCO/VCXO Clock Input—CLK2 Section..............29

Changes to PLL Reference Divider—P Section...........................29

Changes to A and B Counters Section .........................................30

Changes to PLL Digital Lock Detect Section ..............................31

Changes to PLL Analog Lock Detect Section..............................32

Changes to Loss of Reference Section ..........................................32

Changes to FUNCTION Pin Section ...........................................32

Changes to RESETB: 58h<6:5> = 00b (Default) Section ...........32

Changes to SYNCB: 58h<6:5> = 01b Section..............................32

Changes to CLK1 and CLK2 Clock Inputs Section....................33

Control Port Section.......................................................................41

Added Framing a Communication Cycle with CSB Section ....41

Added Communication Cycle—Instruction Plus

Data Section.....................................................................................41

Changes to Write Section...............................................................41

Changes to Read Section................................................................42

Changes to Instruction Word (16 Bits) Section..........................42

Changes to Table 20 ........................................................................42

Changes to MSB/LSB First Transfers Section..............................42

Added Figure 52; Renumbered Sequentially...............................44

Changes to Table 23 ........................................................................45

Changes to Table 24 ........................................................................47

Changes to Power Supply...............................................................54

4/05—Revision 0: Initial Version

Rev. A | Page 3 of 60

AD9511

SPECIFICATIONS

Typical (typ) is given for V_S= 3.3 V 5ꢀ; V_S≤ VCP_S≤ 5.5 V, T_A= 25°C, R_SET= 4.12 kΩ, CPR_SET= 5.1 kΩ, unless otherwise noted.

Minimum (min) and maximum (max) values are given over full V_Sand T_A(−40°C to +85°C) variation.

PLL CHARACTERISTICS

Table 1.

Parameter

Min Typ

Max

Unit

Test Conditions/Comments

REFERENCE INPUTS (REFIN)

Input Frequency

Input Sensitivity

Self-Bias Voltage, REFIN

Self-Bias Voltage, REFINB

Input Resistance, REFIN

Input Resistance, REFINB

Input Capacitance

0

250

MHz

mV p-p

V

kΩ

150

1.45 1.60

1.40 1.50

4.0

4.5

1.75

1.60

5.8

Self-bias voltage of REFIN¹.

Self-bias voltage of REFINB¹.

Self-biased¹.

4.9

5.4

2

6.3

kΩ

pF

Self-biased¹.

PHASE/FREQUENCY DETECTOR (PFD)

PFD Input Frequency

Antibacklash Pulse Width

CHARGE PUMP (CP)

I_CPSink/Source

100

45

MHz

ns

Antibacklash pulse width 0Dh<1:0> = 00b.

Antibacklash pulse width 0Dh<1:0> = 01b.

Antibacklash pulse width 0Dh<1:0> = 10b.

0Dh<1:0> = 00b. (This is the default setting.)

0Dh<1:0> = 01b.

1.3

2.9

6.0

0Dh<1:0> = 10b.

Programmable.

High Value

4.8

0.60

2.5

2.7/10

1

2

1.5

2

mA

%

kΩ

nA

%

With CPR_SET= 5.1 kΩ.

Low Value

Absolute Accuracy

CPR_SETRange

V_CP= VCP_S/2.

I_CPThree-State Leakage

Sink-and-Source Current Matching

I_CPvs. V_CP

I_CPvs. Temperature

RF CHARACTERISTICS (CLK2)²

Input Frequency

0.5 < V_CP< VCP_S− 0.5 V.

V_CP= VCP_S/2 V.

%

1.6

GHz

Frequencies > 1200 MHz (LVPECL) or

800 MHz (LVDS) require a minimum

divide-by-2 (see the Distribution Section).

Input Sensitivity

150

1.6

mV p-p

V

Input Common-Mode Voltage, V_CM

Input Common-Mode Range, V_CMR

Input Sensitivity, Single-Ended

1.5

1.3

1.7

1.8

Self-biased; enables ac coupling.

With 200 mV p-p signal applied.

150

mV p-p CLK2 ac-coupled; CLK2B capacitively

bypassed to RF ground.

Input Resistance

Input Capacitance

4.0

4.8

2

5.6

kΩ

pF

ps

Self-biased.

CLK2 VS. REFIN DELAY

PRESCALER (PART OF N DIVIDER)

500

Difference at PFD.

See the VCO/VCXO Feedback Divider—N (P, A, B)

section.

Prescaler Input Frequency

P = 2 DM (2/3)

600

MHz

P = 4 DM (4/5)

P = 8 DM (8/9)

P = 16 DM (16/17)

P = 32 DM (32/33)

CLK2 Input Frequency for PLL

1000 MHz

1600 MHz

300

MHz

A, B counter input frequency.

Rev. A | Page 4 of 60

AD9511

Parameter

Min Typ

Max

Unit

Test Conditions/Comments

NOISE CHARACTERISTICS

In-Band Noise of the Charge Pump/

Phase Frequency Detector (In-Band

Means Within the LBW of the PLL)

The synthesizer phase noise floor is

estimated by measuring the in-band

phase noise at the output of the VCO and

subtracting 20logN (where N is the

N divider value).

@ 50 kHz PFD Frequency

@ 2 MHz PFD Frequency

@ 10 MHz PFD Frequency

@ 50 MHz PFD Frequency

PLL Figure of Merit

−172

−156

−149

−142

−218 +

10 × log (f_PFD

dBc/Hz

Approximation of the PFD/CP phase noise

floor (in the flat region) inside the PLL loop

bandwidth. When running closed loop this

phase noise is gained up by 20 × log(N)³.

)

PLL DIGITAL LOCK DETECT WINDOW⁴

Signal available at STATUS pin

when selected by 08h<5:2>.

Required to Lock

Selected by Register ODh.

(Coincidence of Edges)

Low Range (ABP 1.3 ns, 2.9 ns Only)

High Range (ABP 1.3 ns, 2.9 ns)

High Range (ABP 6 ns)

3.5

7.5

3.5

ns

<5> = 1b.

<5> = 0b.

To Unlock After Lock (Hysteresis)⁴

Low Range (ABP 1.3 ns, 2.9 ns Only)

High Range (ABP 1.3 ns, 2.9 ns)

High Range (ABP 6 ns)

Selected by Register 0Dh.

<5> = 1b.

<5> = 0b.

7

15

11

ns

<5> = 0b.

¹REFIN and REFINB self-bias points are offset slightly to avoid chatter on an open input condition.

²CLK2 is electrically identical to CLK1; the distribution only input can be used as differential or single-ended input (see the Clock Inputs section).

³Example: −218 + 10 × log(f_PFD) + 20 × log(N) should give the values for the in-band noise at the VCO output.

⁴For reliable operation of the digital lock detect, the period of the PFD frequency must be greater than the unlock-after-lock time.

CLOCK INPUTS

Table 2.

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

CLOCK INPUTS (CLK1, CLK2)¹

Input Frequency

Input Sensitivity

0

1.6

GHz

mV p-p

150²

Jitter performance can be improved with higher slew

rates (greater swing).

Larger swings turn on the protection diodes and can

degrade jitter performance.

Input Level

2³

V p-p

Input Common-Mode Voltage, V_CM

Input Common-Mode Range, V_CMR

Input Sensitivity, Single-Ended

Input Resistance

1.5

1.3

1.6

1.7

1.8

V

Self-biased; enables ac coupling.

With 200 mV p-p signal applied; dc-coupled.

CLK2 ac-coupled; CLK2B ac bypassed to RF ground.

Self-biased.

150

4.8

2

mV p-p

kΩ

pF

4.0

5.6

Input Capacitance

¹CLK1 and CLK2 are electrically identical; each can be used as either differential or single-ended input.

²With a 50 Ω termination, this is −12.5 dBm.

³With a 50 Ω termination, this is +10 dBm.

Rev. A | Page 5 of 60

AD9511

CLOCK OUTPUTS

Table 3.

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

Termination = 50 Ω to V_S− 2 V

Output level 3Dh (3Eh) (3Fh)<3:2> = 10b

See Figure 21

LVPECL CLOCK OUTPUTS

OUT0, OUT1, OUT2; Differential

Output Frequency

Output High Voltage (V_OH)

Output Low Voltage (V_OL)

Output Differential Voltage (V_OD)

LVDS CLOCK OUTPUTS

OUT3, OUT4; Differential

1200

MHz

V

V_S− 1.22

V_S− 2.10

660

V_S− 0.98

V_S− 1.80

810

V_S− 0.93

V_S− 1.67

965

mV

Termination = 100 Ω differential; default

Output level 40h (41h)<2:1> = 01b

3.5 mA termination current

Output Frequency

Differential Output Voltage (V_OD)

Delta V_OD

Output Offset Voltage (V_OS)

Delta V_OS

Short-Circuit Current (I_SA, I_SB)

CMOS CLOCK OUTPUTS

OUT3, OUT4

800

450

25

1.375

25

MHz

mV

V

mV

mA

See Figure 22

250

360

1.23

14

1.125

24

Output shorted to GND

Single-ended measurements;

B outputs: inverted, termination open

Output Frequency

Output Voltage High (V_OH)

Output Voltage Low (V_OL)

250

0.1

MHz

V

With 5 pF load each output; see Figure 23

@ 1 mA load

V_S-0.1

Rev. A | Page 6 of 60

AD9511

TIMING CHARACTERISTICS

Table 4.

Parameter

LVPECL

Min

Typ

Max

Unit

Test Conditions/Comments

Termination = 50 Ω to V_S− 2 V

Output level 3Dh (3Eh) (3Fh)<3:2> = 10b

20% to 80%, measured differentially

80% to 20%, measured differentially

Output Rise Time, t_RP

Output Fall Time, t_FP

PROPAGATION DELAY, t_PECL, CLK-TO-LVPECL OUT¹

130

180

ps

Divide = Bypass

Divide = 2 − 32

Variation with Temperature

OUTPUT SKEW, LVPECL OUTPUTS

OUT1 to OUT0 on Same Part, t_SKP

OUT1 to OUT2 on Same Part, t_SKP

OUT0 to OUT2 on Same Part, t_SKP

All LVPECL OUT Across Multiple Parts, t_{SKP_AB}

Same LVPECL OUT Across Multiple Parts, t_{SKP_AB}

335

375

490

545

0.5

635

695

ps

ps/°C

2

70

15

45

100

45

65

140

80

90

275

130

ps

Ps

ps

2

3

LVDS

Termination = 100 Ω differential

Output level 40h (41h) <2:1> = 01b

3.5 mA termination current

Output Rise Time, t_RL

Output Fall Time, t_FL

PROPAGATION DELAY, t_LVDS, CLK-TO-LVDS OUT¹

200

210

350

ps

20% to 80%, measured differentially

80% to 20%, measured differentially

Delay off on OUT4

OUT3 to OUT4

Divide = Bypass

Divide = 2 − 32

Variation with Temperature

OUTPUT SKEW, LVDS OUTPUTS

OUT3 to OUT4 on Same Part, t_SKV

0.99

1.04

1.33

1.38

0.9

1.59

1.64

ns

ps/°C

Delay off on OUT4

2

−85

+270 ps

450

325

3

All LVDS OUTs Across Multiple Parts, t_{SKV_AB}

Same LVDS OUT Across Multiple Parts, t_{SKV_AB}

ps

3

CMOS

Output Rise Time, t_RC

Output Fall Time, t_FC

B outputs are inverted; termination = open

20% to 80%; C_LOAD= 3 pF

80% to 20%; C_LOAD= 3 pF

681

646

865

992

ps

PROPAGATION DELAY, t_CMOS, CLK-TO-CMOS OUT¹

Delay off on OUT4

Divide = Bypass

Divide = 2 − 32

Variation with Temperature

OUTPUT SKEW, CMOS OUTPUTS

OUT3 to OUT4 on Same Part, t_SKC

1.02

1.07

1.39

1.44

1

1.71

1.76

ns

ps/°C

Delay off on OUT4

2

−140 +145

+300

650

500

3

All CMOS OUT Across Multiple Parts, t_{SKC_AB}

Same CMOS OUT Across Multiple Parts, t_{SKC_AB}

ps

3

LVPECL-TO-LVDS OUT

Output Skew, t_{SKP_V}

LVPECL-TO-CMOS OUT

Output Skew, t_{SKP_C}

LVDS-TO-CMOS OUT

Output Skew, t_{SKV_C}

Everything the same; different logic type

LVPECL to LVDS on same part

0.74

0.88

158

0.92

1.14

353

1.14

1.43

506

ns

ps

Everything the same; different logic type

LVPECL to CMOS on same part

Everything the same; different logic type

LVDS to CMOS on same part

Rev. A | Page 7 of 60

AD9511

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

OUT4; LVDS and CMOS

35h <5:1> 11111b

36h <5:1> 00000b

36h <5:1> 11111b

DELAY ADJUST

Shortest Delay Range⁴

Zero Scale

0.05

0.72

0.36

1.12

0.5

0.68

1.51

ns

LSB

Full Scale

Linearity, DNL

Linearity, INL

0.8

Longest Delay Range⁴

Zero Scale

Full Scale

Linearity, DNL

Linearity, INL

35h <5:1> 00000b

36h <5:1> 00000b

36h <5:1> 11111b

0.20

9.0

0.57

10.2

0.3

0.95

11.6

ns

LSB

0.6

Delay Variation with Temperature

Long Delay Range, 10 ns⁵

Zero Scale

Full Scale

Short Delay Range, 1 ns⁵

0.35

−0.14

ps/°C

Zero Scale

Full Scale

0.51

0.67

ps/°C

¹The measurements are for CLK1. For CLK2, add approximately 25 ps.

²This is the difference between any two similar delay paths within a single device operating at the same voltage and temperature.

³This is the difference between any two similar delay paths across multiple devices operating at the same voltage and temperature.

⁴Incremental delay; does not include propagation delay.

⁵All delays between zero scale and full scale can be estimated by linear interpolation.

Rev. A | Page 8 of 60

AD9511

CLOCK OUTPUT PHASE NOISE

Table 5.

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

CLK1-TO-LVPECL ADDITIVE PHASE NOISE

Distribution Section only; does not

include PLL or external VCO/VCXO

CLK1 = 622.08 MHz, OUT = 622.08 MHz

Divide Ratio = 1

Input slew rate > 1 V/ns

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−125

−132

−140

−148

−153

−154

dBc/Hz

CLK1 = 622.08 MHz, OUT = 155.52 MHz

Divide Ratio = 4

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−128

−140

−148

−155

−161

dBc/Hz

CLK1 = 622.08 MHz, OUT = 38.88 MHz

Divide Ratio = 16

@ 10 Hz Offset

−135

−145

−158

−165

−166

dBc/Hz

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

CLK1 = 491.52 MHz, OUT = 61.44 MHz

Divide Ratio = 8

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−131

−142

−153

−160

−165

dBc/Hz

CLK1 = 491.52 MHz, OUT = 245.76 MHz

Divide Ratio = 2

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−125

−132

−140

−151

−157

−158

dBc/Hz

CLK1 = 245.76 MHz, OUT = 61.44 MHz

Divide Ratio = 4

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−138

−144

−154

−163

−164

−165

dBc/Hz

Rev. A | Page 9 of 60

AD9511

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

CLK1-TO-LVDS ADDITIVE PHASE NOISE

Distribution Section only; does not

include PLL or external VCO/VCXO

CLK1 = 622.08 MHz, OUT= 622.08 MHz

Divide Ratio = 1

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−100

−110

−118

−129

−135

−140

−148

dBc/Hz

CLK1 = 622.08 MHz, OUT = 155.52 MHz

Divide Ratio = 4

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−112

−122

−132

−142

−148

−152

−155

dBc/Hz

CLK1 = 491.52 MHz, OUT = 245.76 MHz

Divide Ratio = 2

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−108

−118

−128

−138

−145

−148

−154

dBc/Hz

CLK1 = 491.52 MHz, OUT = 122.88 MHz

Divide Ratio = 4

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−118

−129

−136

−147

−153

−156

−158

dBc/Hz

CLK1 = 245.76 MHz, OUT = 245.76 MHz

Divide Ratio = 1

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−108

−118

−128

−138

−145

−148

−155

dBc/Hz

CLK1 = 245.76 MHz, OUT = 122.88 MHz

Divide Ratio = 2

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

−118

−127

−137

−147

dBc/Hz

Rev. A | Page 10 of 60

AD9511

Parameter

@ 100 kHz Offset

Min

Typ

Max

Unit

Test Conditions/Comments

−154

−156

−158

dBc/Hz

@ 1 MHz Offset

>10 MHz Offset

CLK1-TO-CMOS ADDITIVE PHASE NOISE

Distribution Section only; does not

include PLL or external VCO/VCXO

CLK1 = 245.76 MHz, OUT = 245.76 MHz

Divide Ratio = 1

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

> 10 MHz Offset

−110

−121

−130

−140

−145

−149

−156

dBc/Hz

CLK1 = 245.76 MHz, OUT = 61.44 MHz

Divide Ratio = 4

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−122

−132

−143

−152

−158

−160

−162

dBc/Hz

CLK1 = 78.6432 MHz, OUT = 78.6432 MHz

Divide Ratio = 1

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

@ 1 MHz Offset

>10 MHz Offset

−122

−132

−140

−150

−155

−158

−160

dBc/Hz

CLK1 = 78.6432 MHz, OUT = 39.3216 MHz

Divide Ratio = 2

@ 10 Hz Offset

@ 100 Hz Offset

@ 1 kHz Offset

@ 10 kHz Offset

@ 100 kHz Offset

>1 MHz Offset

−128

−136

−146

−155

−161

−162

dBc/Hz

Rev. A | Page 11 of 60

AD9511

CLOCK OUTPUT ADDITIVE TIME JITTER

Table 6.

Parameter

Min Typ Max

Unit

Test Conditions/Comments

LVPECL OUTPUT ADDITIVE TIME JITTER

Distribution Section only; does not

include PLL or external VCO/VCXO

CLK1 = 622.08 MHz

Any LVPECL (OUT0 to OUT2) = 622.08 MHz

Divide Ratio = 1

40

fs rms

BW = 12 kHz − 20 MHz (OC-12)

BW = 12 kHz − 20 MHz (OC-3)

CLK1 = 622.08 MHz

Any LVPECL (OUT0 to OUT2) = 155.52 MHz

Divide Ratio = 4

55

fs rms

CLK1 = 400 MHz

215

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Any LVPECL (OUT0 to OUT2) = 100 MHz

Divide Ratio = 4

CLK1 = 400 MHz

215

222

225

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Any LVPECL (OUT0 to OUT2) = 100 MHz

Divide Ratio = 4

Other LVPECL = 100 MHz

Both LVDS (OUT3, OUT4) = 100 MHz

CLK1 = 400 MHz

Interferer(s)

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Any LVPECL (OUT0 to OUT2) = 100 MHz

Divide Ratio = 4

Other LVPECL = 50 MHz

Both LVDS (OUT3, OUT4) = 50 MHz

CLK1 = 400 MHz

Interferer(s)

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Any LVPECL (OUT0 to OUT2) = 100 MHz

Divide Ratio = 4

Other LVPECL = 50 MHz

Both CMOS (OUT3, OUT4) = 50 MHz (B Outputs Off)

CLK1 = 400 MHz

Interferer(s)

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Any LVPECL (OUT0 to OUT2) = 100 MHz

Divide Ratio = 4

Other LVPECL = 50 MHz

Both CMOS (OUT3, OUT4) = 50 MHz (B Outputs On)

LVDS OUTPUT ADDITIVE TIME JITTER

Interferer(s)

Distribution Section only; does not

include PLL or external VCO/VCXO

CLK1 = 400 MHz

264

319

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT3) = 100 MHz

Divide Ratio = 4

CLK1 = 400 MHz

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT4) = 100 MHz

Divide Ratio = 4

Rev. A | Page 12 of 60

AD9511

Parameter

Min Typ Max

Unit

Test Conditions/Comments

CLK1 = 400 MHz

395

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT3) = 100 MHz

Divide Ratio = 4

LVDS (OUT4) = 50 MHz

All LVPECL = 50 MHz

CLK1 = 400 MHz

Interferer(s)

395

367

548

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT4) = 100 MHz

Divide Ratio = 4

LVDS (OUT3) = 50 MHz

All LVPECL = 50 MHz

CLK1 = 400 MHz

Interferer(s)

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT3) = 100 MHz

Divide Ratio = 4

CMOS (OUT4) = 50 MHz (B Outputs Off)

All LVPECL = 50 MHz

Interferer(s)

CLK1 = 400 MHz

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT4) = 100 MHz

Divide Ratio = 4

CMOS (OUT3) = 50 MHz (B Outputs Off)

All LVPECL = 50 MHz

Interferer(s)

CLK1 = 400 MHz

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT3) = 100 MHz

Divide Ratio = 4

CMOS (OUT4) = 50 MHz (B Outputs On)

All LVPECL = 50 MHz

Interferer(s)

CLK1 = 400 MHz

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

LVDS (OUT4) = 100 MHz

Divide Ratio = 4

CMOS (OUT3) = 50 MHz (B Outputs On)

All LVPECL = 50 MHz

Interferer(s)

CMOS OUTPUT ADDITIVE TIME JITTER

Distribution Section only;

does not include PLL or external VCO/VCXO

CLK1 = 400 MHz

275

400

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

Both CMOS (OUT3, OUT4) = 100 MHz (B Output On)

Divide Ratio = 4

CLK1 = 400 MHz

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

CMOS (OUT3) = 100 MHz (B Output On)

Divide Ratio = 4

All LVPECL = 50 MHz

LVDS (OUT4) = 50 MHz

CLK1 = 400 MHz

Interferer(s)

374

fs rms Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

CMOS (OUT3) = 100 MHz (B Output On)

Divide Ratio = 4

All LVPECL = 50 MHz

CMOS (OUT4) = 50 MHz (B Output Off)

Interferer(s)

Rev. A | Page 13 of 60

AD9511

Parameter

Min Typ Max

Unit

Test Conditions/Comments

CLK1 = 400 MHz

555

fs rms

Calculated from SNR of ADC method;

F_C= 100 MHz with A_IN= 170 MHz

CMOS (OUT3) = 100 MHz (B Output On)

Divide Ratio = 4

All LVPECL = 50 MHz

Interferer(s)

CMOS (OUT4) = 50 MHz (B Output On)

DELAY BLOCK ADDITIVE TIME JITTER¹

100 MHz Output

Interferer(s)

Incremental additive jitter

Delay FS = 1 ns (1600 μA, 1C) Fine Adj. 00000

Delay FS = 1 ns (1600 μA, 1C) Fine Adj. 11111

Delay FS = 2 ns (800 μA, 1C) Fine Adj. 00000

Delay FS = 2 ns (800 μA, 1C) Fine Adj. 11111

Delay FS = 3 ns (800 μA, 4C) Fine Adj. 00000

Delay FS = 3 ns (800 μA, 4C) Fine Adj. 11111

Delay FS = 4 ns (400 μA, 4C) Fine Adj. 00000

Delay FS = 4 ns (400 μA, 4C) Fine Adj. 11111

Delay FS = 5 ns (200 μA, 1C) Fine Adj. 00000

Delay FS = 5 ns (200 μA, 1C) Fine Adj. 11111

Delay FS = 11 ns (200 μA, 4C) Fine Adj. 00000

Delay FS = 11 ns (200 μA, 4C) Fine Adj. 00100

0.61

0.73

0.71

1.2

0.86

1.8

1.2

2.1

1.3

2.7

ps

2.0

2.8

¹This value is incremental. That is, it is in addition to the jitter of the LVDS or CMOS output without the delay. To estimate the total jitter, the LVDS or CMOS output jitter

should be added to this value using the root sum of the squares (RSS) method.

PLL AND DISTRIBUTION PHASE NOISE AND SPURIOUS

Table 7.

Parameter

Min Typ

Max Unit

Test Conditions/Comments

PHASE NOISE AND SPURIOUS

Depends on VCO/VCXO selection. Measured at LVPECL

clock outputs; ABP = 6 ns; I_CP= 5 mA; Ref = 30.72 MHz.

VCXO = 245.76 MHz,

VCXO is Toyocom TCO-2112 245.76.

F_PFD= 1.2288 MHz; R = 25, N = 200

245.76 MHz Output

Phase Noise @100 kHz Offset

Spurious

Divide by 1.

Dominated by VCXO phase noise.

First and second harmonics of F_PFD

Below measurement floor.

Divide by 4.

Dominated by VCXO phase noise.

First and second harmonics of F_PFD

Below measurement floor.

<−145

<−97

dBc/Hz

dBc

.

61.44 MHz Output

Phase Noise @100 kHz Offset

Spurious

<−155

<−97

dBc/Hz

dBc

Rev. A | Page 14 of 60

AD9511

SERIAL CONTROL PORT

Table 8.

Parameter

Min

Typ

Max

Unit

Test Conditions/Comments

CSB, SCLK (INPUTS)

CSB and SCLK have 30 kΩ

internal pull-down resistors

Input Logic 1 Voltage

Input Logic 0 Voltage

Input Logic 1 Current

Input Logic 0 Current

Input Capacitance

2.0

V

ꢀA

pF

0.8

1

110

2

SDIO (WHEN INPUT)

Input Logic 1 Voltage

Input Logic 0 Voltage

Input Logic 1 Current

Input Logic 0 Current

Input Capacitance

2.0

2.7

V

nA

pF

0.8

10

2

SDIO, SDO (OUTPUTS)

Output Logic 1 Voltage

Output Logic 0 Voltage

TIMING

Clock Rate (SCLK, 1/t_SCLK

Pulse Width High, t_PWH

Pulse Width Low, t_PWL

SDIO to SCLK Setup, t_DS

SCLK to SDIO Hold, t_DH

V

0.4

25

)

MHz

ns

16

2

1

SCLK to Valid SDIO and SDO, t_DV

CSB to SCLK Setup and Hold, t_S, t_H

CSB Minimum Pulse Width High, t_PWH

6

2

3

ns

FUNCTION PIN

Table 9.

Parameter

Min Typ Max Unit

Test Conditions/Comments

INPUT CHARACTERISTICS

The FUNCTION pin has a 30 kΩ internal pull-down resistor.

This pin should normally be held high. Do not leave NC.

Logic 1 Voltage

Logic 0 Voltage

Logic 1 Current

Logic 0 Current

Capacitance

2.0

V

ꢀA

pF

0.8

1

110

2

RESET TIMING

Pulse Width Low

SYNC TIMING

50

ns

Pulse Width Low

1.5

High speed clock cycles

High speed clock is CLK1 or CLK2, whichever is

used for distribution.

Rev. A | Page 15 of 60

AD9511

STATUS PIN

Table 10.

Parameter

Min Typ Max Unit

Test Conditions/Comments

OUTPUT CHARACTERISTICS

When selected as a digital output (CMOS); there are other modes

in which the STATUS pin is not CMOS digital output. See Figure 37.

Output Voltage High (V_OH)

Output Voltage Low (V_OL)

MAXIMUM TOGGLE RATE

2.7

V

0.4

100

3

MHz

Applies when PLL mux is set to any divider or counter output,

or PFD up/down pulse. Also applies in analog lock detect mode.

Usually debug mode only. Beware that spurs may couple

to output when this pin is toggling.

ANALOG LOCK DETECT

Capacitance

pF

On-chip capacitance; used to calculate RC time

constant for analog lock detect readback. Use a pull-up resistor.

POWER

Table 11.

Parameter

Min Typ Max Unit Test Conditions/Comments

POWER-UP DEFAULT MODE POWER DISSIPATION

550 600

mW

Power-up default state; does not include power

dissipated in output load resistors. No clock.

POWER DISSIPATION

800

mW

All outputs on. Three LVPECL outputs @ 800 MHz,

two CMOS out @ 62 MHz (5 pF load). Does not include

power dissipated in external resistors.

850

mW

All outputs on. Three LVPECL outputs @ 800 MHz,

two CMOS out @ 125 MHz (5 pF load). Does not include

power dissipated in external resistors.

Maximum sleep is entered by setting 0Ah<1:0> = 01b

and 58h<4> = 1b. This powers off the PLL BG and the

distribution BG references. Does not include power

dissipated in terminations.

Set FUNCTION pin for PDB operation by setting

58h<6:5> = 11b. Pull PDB low. Does not include

power dissipated in terminations.

Full Sleep Power-Down

Power-Down (PDB)

35

60

80

mW

POWER DELTA

CLK1, CLK2 Power-Down

Divider, DIV 2 − 32 to Bypass

LVPECL Output Power-Down (PD2, PD3)

10

23

50

15

27

65

25

33

75

mW

For each divider.

For each output. Does not include dissipation

in termination (PD2 only).

LVDS Output Power-Down

CMOS Output Power-Down (Static)

CMOS Output Power-Down (Dynamic)

80

56

115

92

70

110

85

mW

For each output.

For each output. Static (no clock).

For each CMOS output, single-ended. Clocking at

62 MHz with 5 pF load.

150 190

CMOS Output Power-Down (Dynamic)

Delay Block Bypass

125

20

5

165 210

mW

For each CMOS output, single-ended. Clocking at

125 MHz with 5 pF load.

Vs. delay block operation at 1 ns fs with maximum

delay; output clocking at 25 MHz.

24

15

60

40

PLL Section Power-Down

Rev. A | Page 16 of 60

AD9511

TIMING DIAGRAMS

t_CLK1

CLK1

DIFFERENTIAL

80%

t_PECL

LVDS

t_LVDS

20%

t_RL

t_FL

t_CMOS

Figure 4. LVDS Timing, Differential

Figure 2. CLK1/CLK1B to Clock Output Timing, DIV = 1 Mode

SINGLE-ENDED

80%

DIFFERENTIAL

80%

CMOS

3pF LOAD

LVPECL

20%

t_RC

t_FC

t_RP

t_FP

Figure 5. CMOS Timing, Single-Ended, 3 pF Load

Figure 3. LVPECL Timing, Differential

Rev. A | Page 17 of 60

AD9511

ABSOLUTE MAXIMUM RATINGS

Table 12.

With

Respect

to

Parameter or Pin

Min Max

Unit

V

Stresses above those listed under Absolute Maximum Ratings

may cause permanent damage to the device. This is a stress

rating only; functional operation of the device at these or any

other conditions above those indicated in the operational

sections of this specification is not implied. Exposure to

absolute maximum ratings for extended periods may affect

device reliability.

VS

VCP

GND

V_S

−0.3 +3.6

−0.3 +5.8

V

REFIN, REFINB

RSET

CPRSET

CLK1, CLK1B, CLK2, CLK2B

CLK1

CLK2

SCLK, SDIO, SDO, CSB

OUT0, OUT1, OUT2, OUT3,

OUT4

FUNCTION

STATUS

Junction Temperature

Storage Temperature

Lead Temperature (10 sec)

GND

CLK1B

CLK2B

GND

−0.3 V_S+ 0.3

−1.2 +1.2

−0.3 V_S+ 0.3

V

THERMAL CHARACTERISTICS

Thermal Resistance¹

48-Lead LFCSP

θ_JA= 28.5°C/W

GND

−0.3 V_S+ 0.3

150

V

°C

¹Thermal impedance measurements were taken on a 4-layer board in still air,

in accordance with EIA/JESD51-7.

−65

+150

300

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on

the human body and test equipment and can discharge without detection. Although this product features

proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy

electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance

degradation or loss of functionality.

Rev. A | Page 18 of 60

AD9511

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

PIN 1

INDICATOR

REFIN

REFINB

VS

VCP

CP

VS

CLK2

CLK2B

VS

1

2

3

4

5

6

7

8

9

36 VS

35 OUT3

34 OUT3B

33 VS

32 VS

AD9511

TOP VIEW

(Not to Scale)

31 OUT4

30 OUT4B

29 VS

28 VS

CLK1 10

CLK1B 11

FUNCTION 12

27 OUT1

26 OUT1B

25 VS

Figure 6. 48-Lead LFCSP Pin Configuration

Note that the exposed paddle on this package is an electrical connection as well as a thermal enhancement. For the device to

function properly, the paddle must be attached to ground, GND.

Rev. A | Page 19 of 60

AD9511

Table 13. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

2

REFIN

REFINB

VS

PLL Reference Input.

Complementary PLL Reference Input.

Power Supply (3.3 V).

3, 6, 9, 18, 22,

23, 25, 28, 29,

32, 33, 36, 39,

40, 44, 48

4

VCP

Charge Pump Power Supply. It should be greater than or equal to VS.

VCP can be set as high as 5.5 V for VCOs, requiring extended tuning range.

5

7

CP

CLK2

Charge Pump Output.

Clock Input. Used to connect external VCO/VCXO to feedback divider, N. CLK2 also drives the

distribution section of the chip and may be used as a generic clock input when PLL is not used.

8

CLK2B

CLK1

CLK1B

FUNCTION

Complementary Clock Input. Used in conjunction with CLK2.

Clock Input. Drives distribution section of the chip.

Complementary Clock Input. Used in conjunction with CLK1.

Multipurpose Input. May be programmed as a reset (RESETB), sync (SYNCB), or power-down (PDB) pin.

This pin is internally pulled down by a 30 kΩ resistor. If this pin is left NC, the part is in reset by default.

To avoid this, connect this pin to V_Swith a 1 kΩ resistor.

10

11

12

13

14

15

16

17

STATUS

SCLK

SDIO

SDO

CSB

GND

Output Used to Monitor PLL Status and Sync Status.

Serial Data Clock.

Serial Data I/O.

Serial Data Output.

Serial Port Chip Select.

Ground.

19, 24, 37,

38, 43, 46

20

21

26

27

30

31

34

35

41

42

45

47

OUT2B

OUT2

OUT1B

OUT1

OUT4B

OUT4

OUT3B

OUT3

Complementary LVPECL Output.

LVPECL Output.

Complementary LVPECL Output.

LVPECL Output.

Complementary LVDS/Inverted CMOS Output. OUT4 includes a delay block.

LVDS/CMOS Output. OUT4 includes a delay block.

Complementary LVDS/Inverted CMOS Output.

LVDS/CMOS Output.

Complementary LVPECL Output.

LVPECL Output.

OUT0B

OUT0

RSET

Current Set Resistor to Ground. Nominal value = 4.12 kΩ.

Charge Pump Current Set Resistor to Ground. Nominal value = 5.1 kΩ.

CPRSET

Note that the exposed paddle on this package is an electrical connection as well as a thermal enhancement. For the device to

function properly, the paddle must be attached to ground, GND.

Rev. A | Page 20 of 60

AD9511

TERMINOLOGY

Phase Jitter and Phase Noise

Time Jitter

An ideal sine wave can be thought of as having a continuous

and even progression of phase with time from 0 degrees to

360 degrees for each cycle. Actual signals, however, display a

certain amount of variation from ideal phase progression over

time. This phenomenon is called phase jitter. Although many

causes can contribute to phase jitter, one major cause is random

noise, which is characterized statistically as being Gaussian

(normal) in distribution.

Phase noise is a frequency domain phenomenon. In the time

domain, the same effect is exhibited as time jitter. When

observing a sine wave, the time of successive zero crossings is

seen to vary. In a square wave, the time jitter is seen as a

displacement of the edges from their ideal (regular) times of

occurrence. In both cases, the variations in timing from the

ideal are the time jitter. Since these variations are random in

nature, the time jitter is specified in units of seconds root mean

square (rms) or 1 sigma of the Gaussian distribution.

This phase jitter leads to a spreading out of the energy of the

sine wave in the frequency domain, producing a continuous

power spectrum. This power spectrum is usually reported as a

series of values whose units are dBc/Hz at a given offset in

frequency from the sine wave (carrier). The value is a ratio

(expressed in dB) of the power contained within a 1 Hz

bandwidth with respect to the power at the carrier frequency.

For each measurement, the offset from the carrier frequency is

also given.

Time jitter that occurs on a sampling clock for a DAC or an

ADC decreases the SNR and dynamic range of the converter.

A sampling clock with the lowest possible jitter provides the

highest performance from a given converter.

Additive Phase Noise

It is the amount of phase noise that is attributable to the device

or subsystem being measured. The phase noise of any external

oscillators or clock sources has been subtracted. This makes it

possible to predict the degree to which the device impacts the

total system phase noise when used in conjunction with the

various oscillators and clock sources, each of which contribute

their own phase noise to the total. In many cases, the phase

noise of one element dominates the system phase noise.

It is meaningful to integrate the total power contained within

some interval of offset frequencies (for example, 10 kHz to

10 MHz). This is called the integrated phase noise over that

frequency offset interval and can be readily related to the time

jitter due to the phase noise within that offset frequency

interval.

Additive Time Jitter

Phase noise has a detrimental effect on the performance of

ADCs, DACs, and RF mixers. It lowers the achievable dynamic

range of the converters and mixers, although they are affected

in somewhat different ways.

It is the amount of time jitter that is attributable to the device

or subsystem being measured. The time jitter of any external

oscillators or clock sources has been subtracted. This makes it

possible to predict the degree to which the device will impact

the total system time jitter when used in conjunction with the

various oscillators and clock sources, each of which contribute

their own time jitter to the total. In many cases, the time jitter of

the external oscillators and clock sources dominates the system

time jitter.

Rev. A | Page 21 of 60

AD9511

TYPICAL PERFORMANCE CHARACTERISTICS

0.6

0.7

0.6

0.5

0.4

DEFAULT – 3 LVPECL + 2 LVDS (DIV ON)

0.5

3 LVPECL + 2 CMOS (DIV ON)

3 LVPECL + 2 LVDS (DIV BYPASSED)

0.4

3 LVPECL (DIV ON)

2 LVDS (DIV ON)

0.3

0

400

800

0

20

40

60

80

100

120

OUTPUT FREQUENCY (MHz)

Figure 7. Power vs. Frequency—LVPECL, LVDS (PLL Off)

Figure 10. Power vs. Frequency—LVPECL, CMOS (PLL Off)

CLK1 (EVAL BOARD)

REFIN (EVAL BOARD)

3GHz

5MHz

5GHz

3GHz

Figure 8. CLK1 Smith Chart (Evaluation Board)

Figure 11. REFIN Smith Chart (Evaluation Board)

CLK2 (EVAL BOARD)

5MHz

3GHz

Figure 9. CLK2 Smith Chart (Evaluation Board)

Rev. A | Page 22 of 60

AD9511

10

0

10

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

–10

–20

–30

–40

–50

–60

–70

–80

–90

CENTER 61.44MHz

30kHz/

SPAN 300kHz

CENTER 245.75MHz

30kHz/

SPAN 300kHz

Figure 15. Phase Noise, LVPECL, DIV 4, FVCXO = 245.76 MHz,

FOUT = 61.44 MHz, FPFD = 1.2288 MHz, R = 25, N = 200

Figure 12. Phase Noise, LVPECL, DIV 1, FVCXO = 245.76 MHz,

FOUT = 245.76 MHz, FPFD = 1.2288 MHz, R = 25, N = 200

–135

–140

–145

–150

–155

–160

–165

–170

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

100

0.1

1

10

100

CENTER 1.5GHz

250kHz/

SPAN 2.5MHz

PFD FREQUENCY (MHz)

Figure 13. PLL Reference Spurs: VCO 1.5 GHz, FPFD = 1 MHz

Figure 16. Phase Noise (Referred to CP Output) vs. PFD Frequency

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

PUMP DOWN

PUMP UP

PUMP DOWN

PUMP UP

0

0.5

1.0

1.5

2.0

2.5

3.0

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

VOLTAGE ON CP PIN (V)

Figure 14. Charge Pump Output Characteristics @ VCP_S= 3.3 V

Figure 17. Charge Pump Output Characteristics @ VCP_S= 5.0 V

Rev. A | Page 23 of 60

AD9511

1.8

1.7

1.6

1.5

1.4

1.3

1.2

100

600

1100

1600

VERT 500mV/DIV

HORIZ 500ps/DIV

OUTPUT FREQUENCY (MHz)

Figure 18. LVPECL Differential Output @ 800 MHz

Figure 21. LVPECL Differential Output Swing vs. Frequency

750

700

650

600

550

500

100

300

500

700

900

VERT 100mV/DIV

HORIZ 500ps/DIV

OUTPUT FREQUENCY (MHz)

Figure 19. LVDS Differential Output @ 800 MHz

Figure 22. LVDS Differential Output Swing vs. Frequency

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

2pF

10pF

20pF

VERT 500mV/DIV

HORIZ 1ns/DIV

0

100

200

300

400

500

600

OUTPUT FREQUENCY (MHz)

Figure 20. CMOS Single-Ended Output @ 250 MHz with 10 pF Load

Figure 23. CMOS Single-Ended Output Swing vs. Frequency and Load

Rev. A | Page 24 of 60

AD9511

–110

–120

–130

–140

–150

–160

–170

–110

–120

–130

–140

–150

–160

–170

10

100

1k

10k

100k

1M

10M

10

100

1k

10k

100k

1M

10M

OFFSET (Hz)

Figure 24. Additive Phase Noise—LVPECL DIV1, 245.76 MHz

Distribution Section Only

Figure 27. Additive Phase Noise—LVPECL DIV1, 622.08 MHz

–80

–90

–80

–90

–100

–110

–120

–130

–140

–150

–160

–170

–100

–110

–120

–130

–140

–150

–160

–170

10

100

1k

10k

100k

1M

10M

10

100

1k

10k

100k

1M

10M

OFFSET (Hz)

Figure 25. Additive Phase Noise—LVDS DIV1, 245.76 MHz

Figure 28. Additive Phase Noise—LVDS DIV2, 122.88 MHz

–100

–110

–120

–130

–140

–150

–160

–170

–100

–110

–120

–130

–140

–150

–160

–170

10

100

1k

10k

100k

1M

10M

10

100

1k

10k

100k

1M

10M

OFFSET (Hz)

Figure 26. Additive Phase Noise—CMOS DIV1, 245.76 MHz

Figure 29. Additive Phase Noise—CMOS DIV4, 61.44 MHz

Rev. A | Page 25 of 60

AD9511

TYPICAL MODES OF OPERATION

CLOCK DISTRIBUTION ONLY

PLL WITH EXTERNAL VCXO/VCO FOLLOWED BY

CLOCK DISTRIBUTION

It is possible to use only the distribution section whenever the

PLL section is not needed. Some power can be saved by

shutting the PLL block off, as well as by powering down any

unused clock channels (see the Register Map Description

section).

This is the most common operational mode for the AD9511.

An external oscillator (shown as VCO/VCXO) is phase locked

to a reference input frequency applied to REFIN. The loop filter

is usually a passive design. A VCO or a VCXO can be used. The

CLK2 input is connected internally to the feedback divider, N.

The CLK2 input provides the feedback path for the PLL. If the

VCO/VCXO frequency exceeds maximum frequency of the

output(s) being used, an appropriate divide ratio must be set in

the corresponding divider(s) in the Distribution Section. Some

power can be saved by shutting off unused functions, as well as

by powering down any unused clock channels (see the Register

Map and Description section).

In distribution mode, both the CLK1 and CLK2 inputs are

available for distribution to outputs via a low jitter multiplexer

(mux).

PLL

REF

V

REF

AD9511

REFIN

R

N

CHARGE

PUMP

PFD

FUNCTION

CLK1

STATUS

PLL

REF

V

REF

AD9511

CLK2

CLOCK

INPUT 2

CLOCK

INPUT 1

REFIN

REFERENCE

INPUT

R

N

CHARGE

PUMP

LOOP

FILTER

LVPECL

PFD

DIVIDE

FUNCTION

CLK1

STATUS

LVPECL

CLK2

VCXO,

VCO

DIVIDE

LVPECL

DIVIDE

CLOCK

OUTPUTS

LVPECL

LVDS/CMOS

SERIAL

PORT

DIVIDE

ΔT

CLOCK

OUTPUTS

LVDS/CMOS

SERIAL

PORT

Figure 31. Clock Distribution Mode

ΔT

Figure 30. PLL and Clock Distribution Mode

Rev. A | Page 26 of 60

AD9511

PLL WITH EXTERNAL VCO AND BAND-PASS

FILTER FOLLOWED BY CLOCK DISTRIBUTION

An external band-pass filter may be used to try to improve the

phase noise and spurious characteristics of the PLL output. This

option is most appropriate to optimize cost by choosing a less

expensive VCO combined with a moderately priced filter. Note

that the BPF is shown outside of the VCO-to-N divider path,

with the BP filter outputs routed to CLK1. Some power can be

saved by shutting off unused functions, as well as by powering

down any unused clock channels (see the Register Map and

Description section).

PLL

REF

V

REF

AD9511

REFIN

REFERENCE

INPUT

R

N

CHARGE

PUMP

LOOP

FILTER

PFD

FUNCTION

CLK1

STATUS

CLK2

VCO

BPF

LVPECL

DIVIDE

LVPECL

DIVIDE

CLOCK

OUTPUTS

LVDS/CMOS

SERIAL

PORT

Δ

T

Figure 32. AD9511 with VCO and BPF Filter

Rev. A | Page 27 of 60

AD9511

VS GND

RSET

CPRSET VCP

PLL

REF

DISTRIBUTION

REF

AD9511

REFIN

R DIVIDER

N DIVIDER

250MHz

1.6GHz

PHASE

FREQUENCY

DETECTOR

CHARGE

PUMP

REFINB

CP

SYNCB,

RESETB

PDB

FUNCTION

PLL

SETTINGS

STATUS

CLK1

CLK2

1.6GHz

CLK2B

CLK1B

PROGRAMMABLE

DIVIDERS AND

LVPECL

PHASE ADJUST

OUT0

/1, /2, /3... /31, /32

OUT0B

OUT1

1.2GHz

LVPECL

OUT1B

LVPECL

OUT2

OUT2B

SCLK

SDIO

SDO

CSB

LVDS/CMOS

SERIAL

CONTROL

PORT

OUT3

800MHz

LVDS

OUT3B

250MHz

CMOS

OUT4

Δ

T

OUT4B

DELAY

ADJUST

Figure 33. Functional Block Diagram Showing Maximum Frequencies

Rev. A | Page 28 of 60

AD9511

FUNCTIONAL DESCRIPTION

capacitor to a quiet ground. Figure 34 shows the equivalent

circuit of REFIN.

OVERALL

Figure 33 shows a block diagram of the AD9511. The chip

combines a programmable PLL core with a configurable clock

distribution system. A complete PLL requires the addition of a

suitable external VCO (or VCXO) and loop filter. This PLL can

lock to a reference input signal and produce an output that is

related to the input frequency by the ratio defined by the

programmable R and N dividers. The PLL cleans up some jitter

from the external reference signal, depending on the loop

bandwidth and the phase noise performance of the VCO

(VCXO).

V

S

10kΩ

12kΩ

REFIN

150Ω

REFINB

10kΩ

Figure 34. REFIN Equivalent Circuit

VCO/VCXO Clock Input—CLK2

The output from the VCO (VCXO) can be applied to the clock

distribution section of the chip, where it can be divided by any

integer value from 1 to 32. The duty cycle and relative phase of

the outputs can be selected. There are three LVPECL outputs

(OUT0, OUT1, and OUT2) and two outputs that can be either

LVDS or CMOS level outputs (OUT3 or OUT4). OUT4 can

also make use of a variable delay block.

The CLK2 differential input is used to connect an external VCO

or VCXO to the PLL. Only the CLK2 input port has a

connection to the PLL N divider. This input can receive up to

1.6 GHz. These inputs are internally self-biased and must be ac-

coupled via capacitors.

Alternatively, CLK2 may be used as an input to the distribution

section. This is accomplished by setting Register 45h<0> = 0b.

The default condition is for CLK1 to feed the distribution section.

Alternatively, the clock distribution section can be driven

directly by an external clock signal, and the PLL can be powered

off. Whenever the clock distribution section is used alone, there

is no clock clean-up. The jitter of the input clock signal is

passed along directly to the distribution section and may

dominate at the clock outputs.

CLOCK INPUT

STAGE

V

S

CLK

PLL SECTION

CLKB

2.5kΩ

5kΩ

2.5kΩ

The AD9511 consists of a PLL section and a distribution

section. If desired, the PLL section can be used separately from

the distribution section.

5kΩ

The AD9511 has a complete PLL core on-chip, requiring only

an external loop filter and VCO/VCXO. This PLL is based on

the ADF4106, a PLL noted for its superb low phase noise

performance. The operation of the AD9511 PLL is nearly

identical to that of the ADF4106, offering an advantage to those

with experience with the ADF series of PLLs. Differences

include the addition of differential inputs at REFIN and CLK2,

and a different control register architecture. Also, the prescaler

has been changed to allow N as low as 1. The AD9511 PLL

implements the digital lock detect feature somewhat differently

than the ADF4106 does, offering improved functionality at

higher PFD rates. See the Register Map Description section.

Figure 35. CLK1, CLK2 Equivalent Input Circuit

PLL Reference Divider—R

The REFIN/REFINB inputs are routed to reference divider, R,

which is a 14-bit counter. R may be programmed to any value

from 1 to 16383 (a value of 0 results in a divide by 1) via its

control register (OBh<5:0>, OCh<7:0>). The output of the R

divider goes to one of the phase/frequency detector inputs. The

maximum allowable frequency into the phase, frequency

detector (PFD) must not be exceeded. This means that the

REFIN frequency divided by R must be less than the maximum

allowable PFD frequency. See Figure 34.

PLL Reference Input—REFIN

VCO/VCXO Feedback Divider—N (P, A, B)

The REFIN/REFINB pins can be driven by either a differential

or a single-ended signal. These pins are internally self-biased so

that they can be ac-coupled via capacitors. It is possible to dc-

couple to these inputs. If REFIN is driven single-ended, the

unused side (REFINB) should be decoupled via a suitable

The N divider is a combination of a prescaler, P, (3 bits) and two

counters, A (6 bits) and B (13 bits). Although the AD9511’s PLL

is similar to the ADF4106, the AD9511 has a redesigned

prescaler that allows lower values of N. The prescaler has both a

dual modulus (DM) and a fixed divide (FD) mode. The

AD9511 prescaler modes are shown in Table 14.

Rev. A | Page 29 of 60

AD9511

Table 14. PLL Prescaler Modes

Mode

A and B Counters

The AD9511 B counter has a bypass mode (B = 1), which is not

available on the ADF4106. The B counter bypass mode is valid

only when using the prescaler in FD mode. The B counter is

bypassed by writing 1 to the B counter bypass bit (0Ah<6> =

1b). The valid range of the B counter is 3 to 8191. The default

after a reset is 0, which is invalid.

(FD = Fixed Divide

DM = Dual Modulus) Value in 0Ah<4:2>

Divide By

1

2

P/P + 1 = 2/3

P/P + 1 = 4/5

P/P + 1 = 8/9

P/P + 1 = 16/17

P/P + 1 = 32/33

3

FD

000

001

010

011

100

101

110

111

P = 2 DM

P = 4 DM

P = 8 DM

P = 16 DM

P = 32 DM

FD

Note that the A counter is not used when the prescaler is in

FD mode.

Note also that the A/B counters have their own reset bit,

which is primarily intended for testing. The A and B counters

can also be reset using the R, A, and B counters’ shared reset bit

(09h<0>).

When using the prescaler in FD mode, the A counter is not

used, and the B counter may need to be bypassed. The DM

prescaler modes set some upper limits on the frequency, which

can be applied to CLK2. See Table 15.

Determining Values for P, A, B, and R

When operating the AD9511 in a dual-modulus mode, the

input reference frequency, F_REF, is related to the VCO output

frequency, F_VCO.

Table 15. Frequency Limits of Each Prescaler Mode

Mode (DM = Dual Modulus)

P = 2 DM (2/3)

P = 4 DM (4/5)

P = 8 DM (8/9)

P = 16 DM

CLK2

<600 MHz

<1000 MHz

<1600 MHz

F_VCO= (F_REF/R) × (PB + A) = F_REF× N/R

When operating the prescaler in fixed divide mode, the A

counter is not used and the equation simplifies to

P = 32 DM

F_VCO= (F_REF/R) × (PB) = F_REF× N/R

By using combinations of dual modulus and fixed divide

modes, the AD9511 can achieve values of N all the way down to

N = 1. Table 16 shows how a 10 MHz reference input may be

locked to any integer multiple of N. Note that the same value of

N may be derived in different ways, as illustrated by N = 12.

Table 16. P, A, B, R—Smallest Values for N

F_REF

10

R

1

P

1

2

1

2

4

A

X

0

1

2

1

X

0

1

X

0

1

B

1

3

4

5

3

4

5

6

3

N

1

2

3

4

5

6

7

F_VCO

10

20

30

40

50

60

70

Mode

FD

Notes

P = 1, B = 1 (Bypassed)

P = 2, B = 1 (Bypassed)

P = 1, B = 3

P = 1, B = 4

P = 1, B = 5

FD

P = 2, B = 3

DM

FD

DM

FD

P/P + 1 = 2/3, A = 0, B = 3

P/P + 1 = 2/3, A = 1, B = 3

P/P + 1 = 2/3, A = 2, B = 3

P/P + 1 = 2/3, A = 1, B = 4

P = 2, B = 5

P/P + 1 = 2/3, A = 0, B = 5

P/P + 1 = 2/3, A = 1, B = 5

P = 2, B = 6

8

9

80

90

10

11

12

13

100

110

120

130

DM

P/P + 1 = 2/3, A = 0, B = 6

P/P + 1 = 4/5, A = 0, B = 3

P/P + 1 = 4/5, A = 1, B = 3

Rev. A | Page 30 of 60

AD9511

Phase Frequency Detector (PFD) and Charge Pump

Antibacklash Pulse

The PFD takes inputs from the R counter and the N counter

(N = BP + A) and produces an output proportional to the phase

and frequency difference between them. Figure 36 is a

simplified schematic. The PFD includes a programmable delay

element that controls the width of the antibacklash pulse. This

pulse ensures that there is no dead zone in the PFD transfer

function and minimizes phase noise and reference spurs. Two

bits in Register 0Dh <1:0> control the width of the pulse.

The PLL features a programmable antibacklash pulse width that

is set by the value in Register 0Dh<1:0>. The default

antibacklash pulse width is 1.3 ns (0Dh<1:0> = 00b) and

normally should not need to be changed. The antibacklash

pulse eliminates the dead zone around the phase-locked

condition and thereby reduces the potential for certain spurs

that could be impressed on the VCO signal.

STATUS Pin

V

P

The output multiplexer on the AD9511 allows access to various

signals and internal points on the chip at the STATUS pin.

Figure 37 shows a block diagram of the STATUS pin section.

The function of the STATUS pin is controlled by Register

08h<5:2>.

CHARGE

PUMP

UP

HI

D1 Q1

U1

R DIVIDER

CLR1

PLL Digital Lock Detect

PROGRAMMABLE

DELAY

CP

U3

The STATUS pin can display two types of PLL lock detect:

digital (DLD) and analog (ALD). Whenever digital lock detect

is desired, the STATUS pin provides a CMOS level signal, which

can be active high or active low.

ANTIBACKLASH

PULSE WIDTH

CLR2

D2 Q2

DOWN

HI

U2

The digital lock detect has one of two time windows, as selected

by Register 0Dh<5>. The default (ODh<5> = 0b) requires the

signal edges on the inputs to the PFD to be coincident within

9.5 ns to set the DLD true, which then must separate by at least

15 ns to give DLD = false.

N DIVIDER

GND

Figure 36. PFD Simplified Schematic and Timing (In Lock)

The other setting (ODh<5> = 1b) makes these coincidence

times 3.5 ns for DLD = true and 7 ns for DLD = false.

The DLD may be disabled by writing 1 to Register 0Dh<6>.

If the signal at REFIN goes away while DLD is true, the DLD

will not necessarily indicate loss-of-lock. See the Loss of

Reference section for more information.

OFF (LOW) (DEFAULT)

DIGITAL LOCK DETECT (ACTIVE HIGH)

N DIVIDER OUTPUT

SYNC

DETECT

V

S

DIGITAL LOCK DETECT (ACTIVE LOW)

R DIVIDER OUTPUT

ANALOG LOCK DETECT (N-CHANNEL OPEN DRAIN)

A COUNTER OUTPUT

PRESCALER OUTPUT (NCLK)

STATUS

PFD UP PULSE

PFD DOWN PULSE

LOSS OF REFERENCE (ACTIVE HIGH)

TRI-STATE

ANALOG LOCK DETECT (P-CHANNEL OPEN DRAIN)

LOSS OF REFERENCE OR LOCK DETECT (ACTIVE HIGH)

LOSS OF REFERENCE OR LOCK DETECT (ACTIVE LOW)

LOSS OF REFERENCE (ACTIVE LOW)

GND

SYNC DETECT ENABLE

58h <0>

PLL MUX CONTROL

08h <5:2>

Figure 37. STATUS Pin Circuit CLK1 Clock Input

Rev. A | Page 31 of 60

AD9511

User intervention is required to take the part out of this state.

First, 07h<2> = 0b must be written in order to disable the loss-

of-reference circuit, taking the charge pump out of tri-state and

causing LREF to go false. A second write of 07h<2> = 1b is

required to re-enable the loss-of-reference circuit.

PLL Analog Lock Detect

An analog lock detect (ALD) signal may be selected. When

ALD is selected, the signal at the STATUS pin is either an open-

drain P-channel (08h<5:2> = 1100b) or an open-drain N-

channel (08h<5:2> = 0101b).

The analog lock detect signal is true (relative to the selected

mode) with brief false pulses. These false pulses get shorter as

the inputs to the PFD are nearer to coincidence and longer as

they are further from coincidence.

PLL LOOP LOCKS

DLD GOES TRUE

LREF IS FALSE

WRITE 07h<2> = 0

LREF SET FALSE

CHARGE PUMP COMES

OUT OF TRI-STATE

WRITE 07h<2> = 1

LOR ENABLED

n PFD CYCLES WITH

DLD TRUE

(n SET BY 07h<6:5>)

To extract a usable analog lock detect signal, an external RC

network is required to provide an analog filter with the

appropriate RC constant to allow for the discrimination of a

lock condition by an external voltage comparator. A 1 kΩ

resistor in parallel with a small capacitance usually fulfills this

requirement. However, some experimentation may be required

to get the desired operation.

CHECK FOR PRESENCE

CHARGE PUMP

OF REFERENCE.

LREF STAYS FALSE IF

REFERENCE IS DETECTED.

GOES INTO TRI-STATE.

LREF SET TRUE.

MISSING

REFERENCE

DETECTED

Figure 38. Loss of Reference Sequence of Events

The analog lock detect function may introduce some spurious

energy into the clock outputs. It is prudent to limit the use of

the ALD when the best possible jitter/phase noise performance

is required on the clock outputs.

FUNCTION PIN

The FUNCTION pin (12) has three functions that are selected

by the value in Register 58h<6:5>. This pin is internally pulled

down by a 30 kΩ resistor. If this pin is left NC, the part is in

reset by default. To avoid this, connect this pin to V_Swith a

1 kΩ resistor.

Loss of Reference

The AD9511 PLL can warn of a loss-of-reference signal at

REFIN. The loss-of-reference monitor internally sets a flag

called LREF. Externally, this signal can be observed in several

ways on the STATUS pin, depending on the PLL MUX control

settings in Register 08h<5:2>. The LREF alone can be observed

as an active high signal by setting 08h<5:2> = <1010b> or as an

active low signal by setting 08h<5:2> = <1111b>.

RESETB: 58h<6:5> = 00b (Default)

In its default mode, the FUNCTION pin acts as RESETB, which

generates an asynchronous reset or hard reset when pulled low.

The resulting reset writes the default values into the serial

control port buffer registers as well as loading them into the

chip control registers. When the RESETB signal goes high

again, a synchronous sync is issued (see the SYNCB: 58h<6:5>

= 01b section) and the AD9511 resumes operation according to

the default values of the registers.

The loss-of-reference circuit is clocked by the signal from the

VCO, which means that there must be a VCO signal present to

detect a loss of reference.

SYNCB: 58h<6:5> = 01b

The digital lock detect (DLD) block of the AD9511 requires a

PLL reference signal to be present for the digital lock detect

output to be valid. It is possible to have a digital lock detect

indication (DLD = true) that remains true even after a loss-of-

reference signal. For this reason, the digital lock detect signal

alone cannot be relied upon if the reference has been lost. There

is a way to combine the DLD and the LREF into a single signal

at the STATUS pin. Set 08h<5:2> = <1101b> to get a signal that

is the logical OR of the loss-of-lock (inverse of DLD) and the

loss-of-reference (LREF) active high. If an active low version of

this same signal is desired, set 08h<5:2> = <1110b>.

The FUNCTION pin may be used to cause a synchronization or

alignment of phase among the various clock outputs. The

synchronization applies only to clock outputs that:

•

are not powered down

the divider is not masked (no sync = 0b)

are not bypassed (bypass = 0b)

SYNCB is level and rising edge sensitive. When SYNCB is low,

the set of affected outputs are held in a predetermined state,

defined by each divider’s start high bit. On a rising edge, the

dividers begin after a predefined number of fast clock cycles

(fast clock is the selected clock input, CLK1 or CLK2) as

determined by the values in the divider’s phase offset bits.

The reference monitor is enabled only after the DLD signal has

been high for the number of PFD cycles set by the value in

07h<6:5>. This delay is measured in PFD cycles. The delay

ranges from 3 PFD cycles (default) to 24 PFD cycles. When the

reference goes away, LREF goes true and the charge pump goes

into tri-state.

The SYNCB application of the FUNCTION pin is always active,

regardless of whether the pin is also assigned to perform reset

Rev. A | Page 32 of 60

AD9511

or power-down. When the SYNCB function is selected, the

FUNCTION pin does not act as either RESETB or PDB.

Each divider can be configured for divide ratio, phase, and duty

cycle. The phase and duty cycle values that can be selected

depend on the divide ratio that is chosen.

PDB: 58h<6:5> = 11b

Setting the Divide Ratio

The FUNCTION pin may also be programmed to work as an

asynchronous full power-down, PDB. Even in this full power-

down mode, there is still some residual V_Scurrent because

some on-chip references continue to operate. In PDB mode, the

FUNCTION pin is active low. The chip remains in a power-

down state until PDB is returned to logic high. The chip returns

to the settings programmed prior to the power-down.

The divide ratio is determined by the values written via the SCP

to the registers that control each individual output, OUT0 to

OUT4. These are the even numbered registers beginning at 4Ah

and going through 52h. Each of these registers is divided into

bits that control the number of clock cycles the divider output

stays high (high_cycles <3:0>) and the number of clock cycles

the divider output stays low (low_cycles <7:4>). Each value is 4

bits and has the range of 0 to 15.

See the Chip Power-Down or Sleep Mode—PDB section for

more details on what occurs during a PDB initiated power-

down.

The divide ratio is set by

Divide Ratio = (high_cycles + 1) + (low_cycles + 1)

Example 1:

DISTRIBUTION SECTION

As previously mentioned, the AD9511 is partitioned into two

operational sections: PLL and distribution. The PLL Section

was discussed previously. If desired, the distribution section can

be used separately from the PLL section.

Set the Divide Ratio = 2

high_cycles = 0

CLK1 AND CLK2 CLOCK INPUTS

low_cycles = 0

Either CLK1 or CLK2 may be selected as the input to the

distribution section. The CLK1 input can be connected to drive

the distribution section only. CLK1 is selected as the source for

the distribution section by setting Register 45h<0> = 1. This is

the power-up default state.

Divide Ratio = (0 + 1) + (0 + 1) = 2

Example 2:

Set Divide Ratio = 8

CLK1 and CLK2 work for inputs up to 1600 MHz. The jitter

performance is improved by a higher input slew rate. The input

level should be between approximately 150 mV p-p to no more

than 2 V p-p. Anything greater may result in turning on the

protection diodes on the input pins, which could degrade the

jitter performance.

high_cycles = 3

low_cycles = 3

Divide Ratio = (3 + 1) + (3 + 1) = 8

Note that a Divide Ratio of 8 may also be obtained by setting:

high_cycles = 2

See Figure 35 for the CLK1 and CLK2 equivalent input circuit.

These inputs are fully differential and self-biased. The signal

should be ac-coupled using capacitors. If a single-ended input

must be used, this can be accommodated by ac coupling to one

side of the differential input only. The other side of the input

should be bypassed to a quiet ac ground by a capacitor.

low_cycles = 4

Divide Ratio = (2 + 1) + (4 + 1) = 8

Although the second set of settings produce the same divide

ratio, the resulting duty cycle is not the same.

The unselected clock input (CLK1 or CLK2) should be powered

down to eliminate any possibility of unwanted crosstalk

between the selected clock input and the unselected clock input.

Setting the Duty Cycle

The duty cycle and the divide ratio are related. Different divide

ratios have different duty cycle options. For example, if Divide

Ratio = 2, the only duty cycle possible is 50ꢀ. If the Divide

Ratio = 4, the duty cycle may be 25ꢀ, 50ꢀ, or 75ꢀ.

DIVIDERS

Each of the five clock outputs of the AD9511 has its own

divider. The divider can be bypassed to get an output at the

same frequency as the input (1×). When a divider is bypassed, it

is powered down to save power.

The duty cycle is set by

Duty Cycle = (high_cycles + 1)/[(high_cycles + 1) + (low_cycles + 1)]

All integer divide ratios from 1 to 32 may be selected. A divide

ratio of 1 is selected by bypassing the divider.

See Table 17 for the values of the available duty cycles for each

divide ratio.

Rev. A | Page 33 of 60

AD9511

Table 17. Duty Cycle and Divide Ratio

4Ah to 52h

LO<7:4> HI<3:0>

Divide Ratio

Duty Cycle (%)

Divide Ratio

11

12

13

14

15

Duty Cycle (%)

2

3

4

5

6

7

8

9

50

67

33

50

75

25

60

40

80

20

50

67

33

83

17

57

43

71

29

86

14

50

63

38

75

25

88

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56

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67

33

78

22

89

11

50

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90

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55

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73

0

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27

82

18

91

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50

58

42

67

33

75

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83

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92

8

54

46

62

38

69

31

77

23

85

15

92

8

50

57

43

64

36

71

29

79

21

86

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93

7

1

8

0

9

5

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3

7

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8

1

9

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A

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6

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8

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9

1

A

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6

5

7

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A

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C

6

7

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53

47

60

40

67

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27

80

Rev. A | Page 34 of 60

AD9511

4Ah to 52h

LO<7:4> HI<3:0>

4Ah to 52h

LO<7:4>

HI<3:0>

Divide Ratio

15

16

17

18

Duty Cycle (%)

Divide Ratio

19

20

21

22

23

Duty Cycle (%)

20

87

13

93

7

B

1

C

0

D

7

6

8

5

9

4

A

3

B

2

C

1

D

0

E

7

8

6

9

5

A

4

B

3

C

2

D

1

E

0

F

2

C

1

D

0

7

8

6

9

5

A

4

B

3

C

2

D

1

E

0

8

7

9

6

A

5

B

4

C

3

D

2

E

1

F

0

8

9

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A

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B

5

C

4

D

3

E

2

F

1

53

47

58

42

63

37

68

32

74

26

79

21

84

16

50

55

45

60

40

65

35

70

30

75

25

80

20

52

48

57

43

62

38

67

33

71

29

76

24

50

55

45

59

41

64

36

68

32

73

27

52

8

9

7

A

6

B

5

C

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D

3

E

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F

9

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E

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B

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B

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D

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B

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C

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50

56

44

63

38

69

31

75

25

81

19

88

13

94

6

53

47

59

41

65

35

71

29

76

24

82

18

88

12

94

6

50

56

44

61

39

67

33

72

28

78

22

83

17

89

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8

7

9

6

A

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B

4

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3

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2

E

1

F

5

B

A

Rev. A | Page 35 of 60

AD9511

4Ah to 52h

LO<7:4> HI<3:0>

4Ah to 52h

LO<7:4> HI<3:0>

Divide Ratio

Duty Cycle (%)

Divide Ratio

Duty Cycle (%)

23

24

25

26

48

57

43

61

39

65

35

70

30

50

54

46

58

42

63

38

67

33

52

48

56

44

60

40

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36

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B

9

C

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D

7

E

A

C

9

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8

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26

27

28

29

30

31

32

46

58

42

62

38

52

48

56

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59

41

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D

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9

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9

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7

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F

Rev. A | Page 36 of 60

AD9511

In general, by combining the 4-bit phase offset and the Start

H/L bit, there are 32 possible phase offset states (see Table 18).

Divider Phase Offset

The phase of each output may be selected, depending on the

divide ratio chosen. This is selected by writing the appropriate

values to the registers, which set the phase and start high/low

bit for each output. These are the odd numbered registers from

4Bh to 53h. Each divider has a 4-bit phase offset <3:0> and a

start high or low bit <4>.

Table 18. Phase Offset—Start H/L Bit

Phase Offset

(Fast Clock

4Bh to 53h

Rising Edges)

Phase Offset <3:0>

Start H/L <4>

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

0

1

Following a sync pulse, the phase offset word determines how

many fast clock (CLK1 or CLK2) cycles to wait before initiating

a clock output edge. The Start H/L bit determines if the divider

output starts low or high. By giving each divider a different

phase offset, output-to-output delays can be set in increments of

the fast clock period, t_CLK

.

8

9

8

9

Figure 39 shows three dividers, each set for DIV = 4, 50ꢀ duty

cycle. By incrementing the phase offset from 0 to 2, each output

is offset from the initial edge by a multiple of t_CLK

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

10

11

12

13

14

15

0

1

2

3

4

.

0

1

2

3

4

5

6

7

8

9

10 11 12 13 14 15

CLOCK INPUT

CLK

t_CLK

DIVIDER OTUPUTS

DIV = 4, DUTY = 50%

START = 0,

PHASE = 0

START = 0,

PHASE = 1

START = 0,

PHASE = 2

t_CLK

5

6

7

8

2

× t_CLK

Figure 39. Phase Offset—All Dividers Set for DIV = 4, Phase Set from 0 to 2

For example:

9

CLK1 = 491.52 MHz

t_CLK1= 1/491.52 = 2.0345 ns

For DIV = 4

10

11

12

13

14

15

Phase Offset 0 = 0 ns

Phase Offset 1 = 2.0345 ns

Phase Offset 2 = 4.069 ns

The three outputs may also be described as:

OUT1 = 0°

The resolution of the phase offset is set by the fast clock period

(t_CLK) at CLK1 or CLK2. As a result, every divide ratio does not

have 32 unique phase offsets available. For any divide ratio, the

number of unique phase offsets is numerically equal to the

divide ratio (see Table 18):

DIV = 4

OUT2 = 90°

Unique Phase Offsets Are Phase = 0, 1, 2, 3

DIV= 7

OUT3 = 180°

Setting the phase offset to Phase = 4 results in the same relative

phase as the first channel, Phase = 0° or 360°.

Unique Phase Offsets Are Phase = 0, 1, 2, 3, 4, 5, 6

Rev. A | Page 37 of 60

AD9511

DIV = 18

This path adds some jitter greater than that specified for the

nondelay outputs. This means that the delay function should be

used primarily for clocking digital chips, such as FPGA, ASIC,

DUC, and DDC, rather than for data converters. The jitter is

higher for long full scales (~10 ns). This is because the delay

block uses a ramp and trip points to create the variable delay. A

longer ramp means more noise may be introduced.

Unique Phase Offsets Are Phase = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,

11, 12, 13, 14, 15, 16, 17

Phase offsets may be related to degrees by calculating the phase

step for a particular divide ratio:

Phase Step = 360°/(Divide Ratio) = 360°/DIV

Using some of the same examples,

DIV = 4

Calculating the Delay

The following values and equations are used to calculate the

delay of the delay block.

Value of Ramp Current Control Bits (Register 35h or Register 39h

<2:0>) = Iramp_bits

Phase Step = 360°/4 = 90°

Unique Phase Offsets in Degrees Are Phase = 0°, 90°,

180°, 270°

I

_RAMP(μA) = 200 × (Iramp_bits + 1)

No. of Caps = No. of 0s + 1 in Ramp Control Capacitor

(Register 35h or Register 39h <5:3>), that is, 101 = 1 + 1 = 2; 110

= 2; 100 = 2 + 1 = 3; 001 = 2 + 1 = 3; 111 = 0 + 1 = 1)

DIV = 7

Phase Step = 360°/7 = 51.43°

Delay_Range (ns) = 200 × [(No. of Caps + 3)/(I_RAMP)] × 1.3286

Unique Phase Offsets in Degrees Are Phase = 0°, 51.43°,

102.86°, 154.29°, 205.71°, 257.15°, 308.57°

⎛ No.of Caps −1⎞

×10⁻⁴

+

×6

⎜

⎝

⎟

⎠

Offset

(

ns

)

= 0.34 +

(

1600 − I_RAMP

)

DELAY BLOCK

I_RAMP

OUT4 (LVDS/CMOS) includes an analog delay element that

can be programmed (Register 34h to Register 36h) to give

variable time delays (ΔT) in the clock signal passing through

that output.

Delay_Full_Scale (ns) = Delay_Range + Offset

Fine_Adj = Value of Delay Fine Adjust (Register 36h or

Register 3Ah <5:1>), that is, 11111 = 31

CLOCK INPUT

OUT4 ONLY

Delay (ns) = Offset + Delay_Range × Fine_adj × (1/31)

OUTPUTS

÷

N

∅SELECT

The AD9511 offers three different output level choices:

LVDS

LVPECL, LVDS, and CMOS. OUT0 to OUT2 are LVPECL only.

OUT3 and OUT4 can be selected as either LVDS or CMOS.

Each output can be enabled or turned off as needed to save

power.

OUTPUT

DRIVER

Δ

T

CMOS

FINE DELAY ADJUST

(32 STEPS)

FULL-SCALE: 1ns TO 10ns

The simplified equivalent circuit of the LVPECL outputs is

shown in Figure 41.

Figure 40. Analog Delay (OUT4)

The amount of delay that can be used is determined by the

frequency of the clock being delayed. The amount of delay can

approach one-half cycle of the clock period. For example, for a

10 MHz clock, the delay can extend to the full 10 ns maximum

of which the delay element is capable. However, for a 100 MHz

clock (with 50ꢀ duty cycle), the maximum delay is less than

5 ns (or half of the period).

3.3V

OUT

OUTB

OUT4 allows a full-scale delay in the range 1 ns to 10 ns. The

full-scale delay is selected by choosing a combination of ramp

current and the number of capacitors by writing the appropriate

values into Register 35h. There are 32 fine delay settings for

each full scale, set by Register 36h.

GND

Figure 41. LVPECL Output Simplified Equivalent Circuit

Rev. A | Page 38 of 60

AD9511

Table 19. Register 0Ah: PLL Power-Down

3.5mA

<1>

<0>

Mode

0

Normal Operation

0

1

0

Asynchronous Power-Down

Normal Operation

OUT

OUTB

1

Synchronous Power-Down

In asynchronous power-down mode, the device powers down as

soon as the registers are updated.

3.5mA

In synchronous power-down mode, the PLL power-down is

gated by the charge pump to prevent unwanted frequency

jumps. The device goes into power-down on the occurrence of

the next charge pump event after the registers are updated.

Figure 42. LVDS Output Simplified Equivalent Circuit

POWER-DOWN MODES

Chip Power-Down or Sleep Mode—PDB

Distribution Power-Down

The PDB chip power-down turns off most of the functions and

currents in the AD9511. When the PDB mode is enabled, a chip

power-down is activated by taking the FUNCTION pin to a

logic low level. The chip remains in this power-down state until

PDB is brought back to logic high. When woken up, the

AD9511 returns to the settings programmed into its registers

prior to the power-down, unless the registers are changed by

new programming while the PDB mode is active.

The distribution section can be powered down by writing to

Register 58h<3> = 1. This turns off the bias to the distribution

section. If the LVPECL power-down mode is normal operation

<00>, it is possible for a low impedance load on that LVPECL

output to draw significant current during this power-down. If

the LVPECL power-down mode is set to <11>, the LVPECL

output is not protected from reverse bias, and can be damaged

under certain termination conditions.

The PDB power-down mode shuts down the currents on the

chip, except the bias current necessary to maintain the LVPECL

outputs in a safe shutdown mode. This is needed to protect the

LVPECL output circuitry from damage that could be caused by

certain termination and load configurations when tri-stated.

Because this is not a complete power-down, it can be called

sleep mode.

When combined with the PLL power-down, this mode results in

the lowest possible power-down current for the AD9511.

Individual Clock Output Power-Down

Any of the five clock distribution outputs can be powered down

individually by writing to the appropriate registers via the SCP.

The register map details the individual power-down settings for

each output. The LVDS/CMOS outputs may be powered down,

regardless of their output load configuration.

When the AD9511 is in a PDB power-down or sleep mode, the

chip is in the following state:

•

The PLL is off (asynchronous power-down).

All clocks and sync circuits are off.

All dividers are off.

The LVPECL outputs have multiple power-down modes (see

Register 3Dh, Register 3Eh, and Register 3Fh in Table 24).

These give some flexibility in dealing with various output

termination conditions. When the mode is set to <10b>, the

LVPECL output is protected from reverse bias to 2 V_BE+ 1 V. If

the mode is set to <11b>, the LVPECL output is not protected

from reverse bias and can be damaged under certain

termination conditions. This setting also affects the operation

when the distribution block is powered down with Register

58h<3> = 1b (see the Distribution Power-Down section).

All LVDS/CMOS outputs are off.

All LVPECL outputs are in safe off mode.

The serial control port is active, and the chip responds to

commands.

Individual Circuit Block Power-Down

If the AD9511 clock outputs must be synchronized to each

other, a SYNC (see the Single-Chip Synchronization section) is

required upon exiting power-down mode.

Many of the AD9511 circuit blocks (CLK1, CLK2, and REFIN,

and so on) can be powered down individually. This gives

flexibility in configuring the part for power savings whenever

certain chip functions are not needed.

PLL Power-Down

The PLL section of the AD9511 can be selectively powered

down. There are three PLL power-down modes, set by the

values in Register 0Ah<1:0>, as shown in Table 19.

Rev. A | Page 39 of 60

AD9511

Synchronization of two or more AD9511s requires a fast clock

and a slow clock. The fast clock can be up to 1 GHz and may be

the clock driving the master AD9511 CLK1 input or one of the

outputs of the master. The fast clock acts as the input to the

distribution section of the slave AD9511 and is connected to its

CLK1 input. The PLL may be used on the master, but the slave

PLL is not used.

RESET MODES

The AD9511 has several ways to force the chip into a reset

condition.

Power-On Reset—Start-Up Conditions when VS is

Applied

A power-on reset (POR) is issued when the VS power supply is

turned on. This initializes the chip to the power-on conditions

that are determined by the default register settings. These are

indicated in the default value column of Table 23.

The slow clock is the clock that is synchronized across the two

chips. This clock must be no faster than one-fourth of the fast

clock, and no greater than 250 MHz. The slow clock is taken

from one of the outputs of the master AD9511 and acts as the

REFIN (or CLK2) input to the slave AD9511. One of the

outputs of the slave must provide this same frequency back to

the CLK2 (or REFIN) input of the slave.

Asynchronous Reset via the FUNCTION Pin

As mentioned in the FUNCTION Pin section, a hard reset,

RESETB: 58h<6:5> = 00b (Default), restores the chip to the

default settings.

Multichip synchronization is enabled by writing to Register

58h<0> = 1b on the slave AD9511. When this bit is set, the

STATUS pin becomes the output for the SYNC signal. A low

signal indicates an in-sync condition, and a high indicates an

out-of-sync condition.

Soft Reset via the Serial Port

The serial control port allows a soft reset by writing to

Register 00h<5> = 1b. When this bit is set, the chip executes a

soft reset. This restores the default values to the internal

registers, except for Register 00h itself.

Register 58h<1> selects the number of fast clock cycles that are

the maximum separation of the slow clock edges that are

considered synchronized. When 58h<1> = 0b (default), the

slow clock edges must be coincident within 1 to 1.5 high speed

clock cycles. If the coincidence of the slow clock edges is closer

than this amount, the SYNC flag stays low. If the coincidence of

the slow clock edges is greater than this amount, the SYNC flag

is set high. When Register 58h<1> = 1b, the amount of

coincidence required is 0.5 fast clock cycles to 1 fast clock

cycles.

This bit is not self-clearing. The bit must be written to

00h<5> = 0b for the operation of the part to continue.

SINGLE-CHIP SYNCHRONIZATION

SYNCB—Hardware SYNC

The AD9511 clocks can be synchronized to each other at any

time. The outputs of the clocks are forced into a known state

with respect to each other and then allowed to continue

clocking from that state in synchronicity. Before a

synchronization is done, the FUNCTION Pin must be set as the

SYNCB: 58h<6:5> = 01b input (58h<6:5> = 01b).

Synchronization is done by forcing the FUNCTION pin low,

creating a SYNCB signal and then releasing it.

Whenever the SYNC flag is set (high), indicating an out-of-sync

condition, a SYNCB signal applied simultaneously at the

FUNCTION pins of both AD9511s brings the slow clocks into

synchronization.

See the SYNCB: 58h<6:5> = 01b section for a more detailed

description of what happens when the SYNCB: 58h<6:5> = 01b

signal is issued.

AD9511

MASTER

OUTN

FAST CLOCK

<1GHz

Soft SYNC—Register 58h<2>

FUNCTION

OUTM

A soft SYNC may be issued by means of a bit in the Register

58h<2>. This soft SYNC works the same as the SYNCB, except

that the polarity is reversed. A 1 written to this bit forces the

clock outputs into a known state with respect to each other.

When a 0 is subsequently written to this bit, the clock outputs

continue clocking from that state in synchronicity.

SLOW CLOCK

(SYNCB)

<250MHz

F

SYNC

SYNCB

CLK2

REFIN

AD9511

SLAVE

SLOW

F

SYNC

CLOCK

<250MHz

OUTY

MULTICHIP SYNCHRONIZATION

FAST CLOCK

<1GHz

SYNC

DETECT

CLK1

The AD9511 provides a means of synchronizing two or more

AD9511s. This is not an active synchronization; it requires user

monitoring and action. The arrangement of two AD9511s to be

synchronized is shown in Figure 43.

FUNCTION

(SYNCB)

STATUS

(SYNC)

Figure 43. Multichip Synchronization

Rev. A | Page 40 of 60

AD9511

SERIAL CONTROL PORT

The AD9511 serial control port is a flexible, synchronous, serial

communications port that allows an easy interface with many

industry-standard microcontrollers and microprocessors. The

AD9511 serial control port is compatible with most

not brought high at the end of each write or read cycle (on a

byte boundary), the last byte is not loaded into the register

buffer.

CSB stall high is supported in modes where three or fewer bytes

of data (plus instruction data) are transferred (W1:W0 must be

set to 00, 01, or 10, see Table 20). In these modes, CSB can

temporarily return high on any byte boundary, allowing time

for the system controller to process the next byte. CSB can go

high on byte boundaries only and can go high during either

part (instruction or data) of the transfer. During this period, the

serial control port state machine enters a wait state until all data

has been sent. If the system controller decides to abort the

transfer before all of the data is sent, the state machine must be

reset by either completing the remaining transfer or by

synchronous transfer formats, including both the Motorola SPI®

and Intel® SSR protocols. The serial control port allows

read/write access to all registers that configure the AD9511.

Single or multiple byte transfers are supported, as well as MSB

first or LSB first transfer formats. The AD9511 serial control

port can be configured for a single bidirectional I/O pin (SDIO

only) or for two unidirectional I/O pins (SDIO/SDO).

SERIAL CONTROL PORT PIN DESCRIPTIONS

SCLK (serial clock) is the serial shift clock. This pin is an input.

SCLK is used to synchronize serial control port reads and

writes. Write data bits are registered on the rising edge of this

clock, and read data bits are registered on the falling edge. This

pin is internally pulled down by a 30 kΩ resistor to ground.

returning the CSB low for at least one complete SCLK cycle (but

less than eight SCLK cycles). Raising the CSB on a nonbyte

boundary terminates the serial transfer and flushes the buffer.

In the streaming mode (W1:W0 = 11b), any number of data

bytes can be transferred in a continuous stream. The register

address is automatically incremented or decremented (see the

MSB/LSB First Transfers section). CSB must be raised at the

end of the last byte to be transferred, thereby ending the

stream mode.

SDIO (serial data input/output) is a dual-purpose pin and acts

as either an input only or as both an input/output. The AD9511

defaults to two unidirectional pins for I/O, with SDIO used as

an input and SDO as an output. Alternatively, SDIO can be used

as a bidirectional I/O pin by writing to the SDO enable register

at 00h<7> = 1b.

Communication Cycle—Instruction Plus Data

SDO (serial data out) is used only in the unidirectional I/O

mode (00h<7> = 0b, default) as a separate output pin for

reading back data. The AD9511 defaults to this I/O mode.

Bidirectional I/O mode (using SDIO as both input and output)

may be enabled by writing to the SDO enable register at

00h<7> = 1b.

There are two parts to a communication cycle with the AD9511.

The first writes a 16-bit instruction word into the AD9511,

coincident with the first 16 SCLK rising edges. The instruction

word provides the AD9511 serial control port with information

regarding the data transfer, which is the second part of the

communication cycle. The instruction word defines whether

the upcoming data transfer is a read or a write, the number of

bytes in the data transferred, and the starting register address

for the first byte of the data transfer.

CSB (chip select bar) is an active low control that gates the read

and write cycles. When CSB is high, SDO and SDIO are in a

high impedance state. This pin is internally pulled down by a

30 kΩ resistor to ground. It should not be left NC or tied low.

See the Framing a Communication Cycle with CSB section on

the use of the CSB in a communication cycle.

Write

If the instruction word is for a write operation (I15 = 0b), the

second part is the transfer of data into the serial control port

buffer of the AD9511. The length of the transfer (1, 2, 3 bytes or

streaming mode) is indicated by two bits (W1:W0) in the

instruction byte. CSB can be raised after each sequence of eight

bits to stall the bus (except after the last byte, where it ends the

cycle). When the bus is stalled, the serial transfer resumes when

CSB is lowered. Stalling on nonbyte boundaries resets the serial

control port.

SCLK (PIN 14)

AD9511

SDIO (PIN 15)

SERIAL

SDO (PIN 16)

CONTROL

PORT

CSB (PIN 17)

Figure 44. Serial Control Port

GENERAL OPERATION OF SERIAL CONTROL PORT

Framing a Communication Cycle with CSB

Each communication cycle (a write or a read operation) is gated

by the CSB line. CSB must be brought low to initiate a

communication cycle. CSB must be brought high at the

completion of a communication cycle (see Figure 52). If CSB is

Since data is written into a serial control port buffer area, not

directly into the AD9511’s actual control registers, an additional

operation is needed to transfer the serial control port buffer

contents to the actual control registers of the AD9511, thereby

causing them to take effect. This update command consists of

Rev. A | Page 41 of 60

AD9511

writing to Register 5Ah<0> = 1b. This update bit is self-clearing

(it is not required to write 0 to it to clear it). Since any number

of bytes of data can be changed before issuing an update

command, the update simultaneously enables all register

changes since any previous update.

For a write, the instruction word is followed by the number of

bytes of data indicated by Bits W1:W0, which is interpreted

according to Table 20.

Table 20. Byte Transfer Count

W1

W0

Bytes to Transfer

0

1

0

1

0

1

2

3

4

Phase offsets or divider synchronization is not effective until a

SYNC is issued (see the Single-Chip Synchronization section).

Read

If the instruction word is for a read operation (I15 = 1b), the

next N × 8 SCLK cycles clock out the data from the address

specified in the instruction word, where N is 1 to 4 as

determined by W1:W0. The readback data is valid on the falling

edge of SCLK.

A12:A0: These 13 bits select the address within the register map

that is written to or read from during the data transfer portion

of the communications cycle. The AD9511 does not use all of

the 13-bit address space. Only Bits A6:A0 are needed to cover

the range of the 5Ah registers used by the AD9511. Bits A12:A7

must always be 0b. For multibyte transfers, this address is the

starting byte address. In MSB first mode, subsequent bytes

increment the address.

The default mode of the AD9511 serial control port is

unidirectional mode; therefore, the requested data appears on

the SDO pin. It is possible to set the AD9511 to bidirectional

mode by writing the SDO enable register at 00h<7> = 1b. In

bidirectional mode, the readback data appears on the SDIO pin.

MSB/LSB FIRST TRANSFERS

The AD9511 instruction word and byte data may be MSB first

or LSB first. The default for the AD9511 is MSB first. The LSB

first mode may be set by writing 1b to Register 00h<6>. This

takes effect immediately (since it only affects the operation of

the serial control port) and does not require that an update be

executed. Immediately after the LSB first bit is set, all serial

control port operations are changed to LSB first order.

A readback request reads the data that is in the serial control

port buffer area, not the active data in the AD9511’s actual

control registers.

SCLK

SDIO

SDO

When MSB first mode is active, the instruction and data bytes

must be written from MSB to LSB. Multibyte data transfers in

MSB first format start with an instruction byte that includes the

register address of the most significant data byte. Subsequent

data bytes must follow in order from high address to low

address. In MSB first mode, the serial control port internal

address generator decrements for each data byte of the

multibyte transfer cycle.

UPDATE

REGISTERS

5Ah <0>

CSB

SERIAL

CONTROL

AD9511

PORT

CORE

Figure 45. Relationship Between Serial Control Port Register Buffers and

Control Registers of the AD9511

When LSB_First = 1b (LSB first), the instruction and data bytes

must be written from LSB to MSB. Multibyte data transfers in

LSB first format start with an instruction byte that includes the

register address of the least significant data byte followed by

multiple data bytes. The serial control port internal byte address

generator increments for each byte of the multibyte transfer

cycle.

The AD9511 uses Address 00h to Address 5Ah. Although the

AD9511 serial control port allows both 8-bit and 16-bit

instructions, the 8-bit instruction mode provides access to five

address bits (A4 to A0) only, which restricts its use to the

address space 00h to 01F. The AD9511 defaults to 16-bit

instruction mode on power-up. The 8-bit instruction mode

(although defined for this serial control port) is not useful for

the AD9511; therefore, it is not discussed further in this data

sheet.

The AD9511 serial control port register address decrements

from the register address just written toward 0000h for

multibyte I/O operations if the MSB first mode is active

(default). If the LSB first mode is active, the serial control port

register address increments from the address just written

toward 1FFFh for multibyte I/O operations.

THE INSTRUCTION WORD (16 BITS)

W

The MSB of the instruction word is R/ , which indicates

whether the instruction is a read or a write. The next two bits,

W1:W0, indicate the length of the transfer in bytes. The final 13

bits are the addresses (A12:A0) at which to begin the read or

write operation.

Unused addresses are not skipped during multibyte I/O

operations; therefore, it is important to avoid multibyte I/O

operations that would include these addresses.

Rev. A | Page 42 of 60

AD9511

Table 21. Serial Control Port, 16-Bit Instruction Word, MSB First

MSB

LSB

I15

I14

I13

I12

I11

I10

I9

I8

I7

I6

I5

I4

I3

I2

I1

I0

W

R/

W1

W0

A12 = 0

A11 = 0

A10 = 0

A9 = 0

A8 = 0

A7 = 0

A6

A5

A4

A3

A2

A1

A0

CSB

SCLK DON'T CARE

DON'T CARE

SDIO

R/W W1 W0 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0

16-BIT INSTRUCTION HEADER REGISTER (N) DATA REGISTER (N – 1) DATA

Figure 46. Serial Control Port Write—MSB First, 16-Bit Instruction, 2 Bytes of Data

CSB

SCLK

DON'T CARE

R/W W1 W0 A12A11A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0

DON'T CARE

SDIO

D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0

SDO DON'T CARE

16-BIT INSTRUCTION HEADER

REGISTER (N) DATA

REGISTER (N – 1) DATA

REGISTER (N – 2) DATA

REGISTER (N – 3) DATA

DON'T

CARE

Figure 47. Serial Control Port Read—MSB First, 16-Bit Instruction, 4 Bytes od Data

t_DS

t_HI

t_S

t_H

t_CLK

t_DH

t_LO

CSB

DON'T CARE

SCLK

SDIO

R/W

W1

W0

A12

A11

A10

A9

A8

A7

A6

A5

D4

D3

D2

D1

D0

DON'T CARE

Figure 48. Serial Control Port Write—MSB First, 16-Bit Instruction, Timing Measurements

CSB

SCLK

t_DV

SDIO

SDO

DATA BIT N

DATA BIT N– 1

Figure 49. Timing Diagram for Serial Control Port Register Read

CSB

SCLK DON'T CARE

DON'T CARE

A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 W0 W1 R/W D0 D1 D2 D3 D4 D5 D6 D7 D0 D1 D2 D3 D4 D5 D6 D7

16-BIT INSTRUCTION HEADER REGISTER (N) DATA REGISTER (N + 1) DATA

DON'T CARE

SDIO

Figure 50. Serial Control Port Write—LSB First, 16-Bit Instruction, 2 Bytes Data

Rev. A | Page 43 of 60

AD9511

t_S

t_H

CSB

t_CLK

t_HI

t_LO

t_DS

SCLK

SDIO

t_DH

BI N

BI N + 1

Figure 51. Serial Control Port Timing—Write

Table 22. Serial Control Port Timing

Parameter

Description

t_DS

t_DH

t_CLK

t_S

Setup time between data and rising edge of SCLK

Hold time between data and rising edge of SCLK

Period of the clock

Setup time between CSB and SCLK

t_H

Hold time between CSB and SCLK

t_HI

t_LO

Minimum period that SCLK should be in a logic high state

Minimum period that SCLK should be in a logic low state

CSB TOGGLE INDICATES

CYCLE COMPLETE

t_PWH

CSB

16 INSTRUCTION BITS + 8 DATA BITS

COMMUNICATION CYCLE 1

16 INSTRUCTION BITS + 8 DATA BITS

SCLK

SDIO

COMMUNICATION CYCLE 2

TIMING DIAGRAM FOR TWO SUCCESSIVE COMMUNICATION CYCLES. NOTE THAT CSB MUST

BE TOGGLED HIGH AND THEN LOW AT THE COMPLETION OFA COMMUNICATION CYCLE.

Figure 52. Use of CSB to Define Communications Cycles

Rev. A | Page 44 of 60

AD9511

REGISTER MAP AND DESCRIPTION

SUMMARY TABLE

Table 23. AD9511 Register Map

Def.

Value

Addr

Bit 0

(Hex) Parameter

Bit 7 (MSB)

Bit 6

Bit 5

Soft

Reset

Bit 4

Long

Instruction

Bit 3

Bit 2

Bit 1

(LSB)

(Hex) Notes

00

Serial

SDO Inactive

(Bidirectional

Mode)

LSB

First

Not Used

10

Control Port

Configuration

01,

02,

03

Not Used

PLL

PLL Starts

in Power-

Down

04

05

06

07

08

09

0A

A Counter

B Counter

PLL 1

Not Used

6-Bit A Counter <5:0>

13-Bit B Counter Bits 12:8 (MSB) <4:0>

13-Bit B Counter Bits 7:0 (LSB) <7:0>

00

N Divider

(A)

N Divider

(B)

N Divider

(B)

Not

Used

LOR Lock_Del

<6:5>

Not Used

LOR

Not Used

Enable

PLL 2

Not

PFD

PLL Mux Select <5:2>

Signal on STATUS pin

CP Mode <1:0>

Used

Polarity

PLL 3

Not

Used

CP Current <6:4>

Not

Reset R

Reset N Reset All 00

Used Counter Counter Counters

PLL 4

Not

B

Not

Prescaler P <4:2> Power-Down <1:0> 01

N Divider

(P)

Used

Bypass

Used

0B

0C

0D

R Divider

PLL 5

Not Used

14-Bit R Divider Bits 13:8 (MSB) <5:0>

00

R Divider

14-Bit R Divider Bits 13:8 (MSB) <7:0>

Not

Used

Digital

Lock

Det

Digital

Lock

Det

Not Used

Antibacklash

Pulse Width <1:0>

Enable Window

OE-

33

Not Used

FINE DELAY

ADJUST

Fine

Delays

Bypassed

34

35

Delay Bypass 4

Not Used

Ramp Capacitor <5:3>

Bypass

01

00

Bypass

Delay

Not Used

Ramp Current <2:0>

Max.

Full-Scale 4

Delay

Full-Scale

36

Delay Fine

Adjust 4

Not Used

5-Bit Fine Delay <5:1>

Not

Used

00

Min. Delay

Value

37,

38,

39,

3A,

3B,

3C

Not Used

Rev. A | Page 45 of 60

AD9511

Def.

Value

Addr

Bit 0

(Hex) Parameter

Bit 7 (MSB)

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

(LSB)

(Hex) Notes

OUTPUTS

3D

3E

3F

40

LVPECL OUT0

LVPECL OUT1

LVPECL OUT2

Not Used

Output Level

<3:2>

Power-Down <1:0> 08

ON

Not Used

Output Level

<3:2>

ON

Output Level

<3:2>

ON

LVDS_CMOS

OUT 3

Not Used

CMOS

Inverted

Driver On

Logic

Select

Output Level

<2:1>

Output

Power

02

LVDS, ON

41

LVDS_CMOS

OUT 4

Not Used

CMOS

Inverted

Driver On

Logic

Select

Output Level

<2:1>

Output

Power

LVDS, ON

42,

43,

44

Not Used

CLK1 AND

CLK2

Input

Receivers

45

Clocks Select,

Power-Down

(PD) Options

Not Used

CLKs in

PD

REFIN PD

CLK

to

PLL

PD

CLK2

PD

CLK1

PD

Select

CLK IN

01

All Clocks

ON, Select

CLK1

46,

Not Used

47,

48, 49

DIVIDERS

Divider 0

4A

4B

Low Cycles <7:4>

High Cycles <3:0>

Phase Offset <3:0>

00

Divide by 2

Phase = 0

Bypass

No

Force

Start H/L

Sync

4C

4D

Divider 1

Low Cycles <7:4>

High Cycles <3:0>

Phase Offset <3:0>

11

00

Divide by 4

Phase = 0

No

Force

Sync

4E

4F

Divider 2

Low Cycles <7:4>

High Cycles <3:0>

Phase Offset <3:0>

33

00

Divide by 8

Phase = 0

No

Force

Sync

50

51

Divider 3

Low Cycles <7:4>

High Cycles <3:0>

Phase Offset <3:0>

00

Divide by 2

Phase = 0

No

Force

Sync

52

53

Divider 4

Low Cycles <7:4>

High Cycles <3:0>

Phase Offset <3:0>

11

00

Divide by 4

Phase = 0

No

Force

Sync

54,

55,

56,

57

Not Used

FUNCTION

58

FUNCTION

Pin and Sync

Not

Used

Set FUNCTION Pin

PD Sync

PD All

Ref

Sync

Reg

Sync

Select

Sync

Enable

00

FUNCTION

Pin =

RESETB

59

5A

Not Used

Update

Not Used

Update

Self-

Registers

Clearing

Bit

END

Rev. A | Page 46 of 60

AD9511

REGISTER MAP DESCRIPTION

Table 24 lists the AD9511 control registers by hexadecimal address. A specific bit or range of bits within a register is indicated by angle

brackets. For example, <3> refers to Bit 3, while <5:2> refers to the range of bits from Bit 5 through Bit 2. Table 24 describes the

functionality of the control registers on a bit-by-bit basis. For a more concise (but less descriptive) table, see Table 23.

Table 24. AD9511 Register Descriptions

Reg.

Addr.

(Hex)

Bit(s) Name

Description

Serial Control Port Any changes to this register takes effect immediately. Register 5Ah<0> Update Registers does not

Configuration

have to be written.

Not Used.

00

<3:0>

<4> Long Instruction When this bit is set (1), the instruction phase is 16 bits. When clear (0), the instruction phase is 8 bits.

The default, and only, mode for this part is long instruction (Default = 1b).

00

<5> Soft Reset

When this bit is set (1), the chip executes a soft reset, restoring default values to the internal

registers, except for this register, 00h. This bit is not self-clearing. A clear (0) has to be written

to it to clear it.

<6> LSB First

When this bit is set (1), the input and output data is oriented as LSB first. Additionally, register

addressing increments. If this bit is clear (0), data is oriented as MSB first and register addressing

decrements. (Default = 0b, MSB first).

<7> SDO Inactive

(Bidirectional

Mode)

When set (1), the SDO pin is tri-state and all read data goes to the SDIO pin. When clear (0), the

SDO is active (unidirectional mode). (Default = 0b).

Not Used

<7:0>

01

02

03

Not Used.

<7:0>

PLL Settings

04

05

06

07

<5:0> A Counter

<7:6>

6-Bit A Counter <5:0>.

Not Used.

<4:0> B Counter MSBs

<7:5>

13-Bit B Counter (MSB) <12:8>.

Not Used.

<7:0> B Counter LSBs

<1:0>

13-Bit B Counter (LSB) <7:0>.

Not Used.

<2> LOR Enable

<4:3>

1 = Enables the Loss-of-Reference (LOR) Function; (Default = 0b).

Not Used.

<6:5> LOR Initial Lock

Detect Delay

LOR Initial Lock Detect Delay. Once a lock detect is indicated, this is the number of phase frequency

detector (PFD) cycles that occur prior to turning on the LOR monitor.

<6>

<5>

LOR Initial Lock Detect Delay

3 PFD Cycles (Default)

6 PFD Cycles

12 PFD Cycles

24 PFD Cycles

0

1

0

1

0

1

07

08

<7>

Not Used

<1:0> Charge Pump

Mode

<1>

0

<0>

0

1

Charge Pump Mode

Tri-Stated (Default)

Pump-Up

1

0

Pump-Down

1

Normal Operation

Rev. A | Page 47 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

Description

08

<5:2> PLL Mux Control

<5>

0

1

<4>

<3> <2> MUXOUT—Signal on STATUS Pin

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

0

1

Off (Signal Goes Low) (Default)

Digital Lock Detect (Active High)

N Divider Output

Digital Lock Detect (Active Low)

R Divider Output

Analog Lock Detect (N Channel, Open-Drain)

A Counter Output

Prescaler Output (NCLK)

PFD Up Pulse

PFD Down Pulse

Loss-of-Reference (Active High)

Tri-State

Analog Lock Detect (P Channel, Open-Drain)

Loss-of-Reference or Loss-of-Lock (Inverse of DLD)

(Active High)

1

0

Loss-of-Reference or Loss-of-Lock (Inverse of DLD)

(Active Low)

1

Loss-of-Reference (Active Low)

MUXOUT is the PLL portion of the STATUS output MUX.

08

<6> Phase-Frequency 0 = Negative (Default), 1 = Positive.

Detector (PFD)

Polarity

08

09

<7>

Not Used.

<0> Reset All Counters 0 = Normal (Default), 1 = Reset R, A, and B Counters.

<1> N-Counter Reset 0 = Normal (Default), 1 = Reset A and B Counters.

<2> R-Counter Reset 0 = Normal (Default), 1 = Reset R Counter.

<3>

Not Used.

<6:4> Charge Pump (CP)

Current Setting

<6>

<5>

0

<4>

0

I_CP(mA)

0.60

1.2

0

1

0

1

0

1.8

0

1

2.4

1

0

3.0

1

0

1

3.6

1

0

4.2

1

4.8

Default = 000b.

These currents assume: CPR_SET= 5.1 kΩ.

Actual current can be calculated by: CP_lsb = 3.06/CPR_SET

Not Used.

.

09

<7>

Rev. A | Page 48 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

Description

0A

<1:0> PLL Power-Down 01 = Asynchronous Power-Down (Default).

<1>

0

<0>

0

Mode

Normal Operation

0

1

0

Asynchronous Power-Down

Normal Operation

1

Synchronous Power-Down

0A

<4:2> Prescaler Value

(P/P+1)

<4>

0

<3>

0

1

<2> Mode Prescaler Mode

0

1

0

1

0

1

0

1

FD

Divide by 1

Divide by 2

2/3

4/5

8/9

DM

FD

1

0

16/17

1

32/33

Divide by 3

DM = Dual Modulus, FD = Fixed Divide.

Not Used.

0A

<5>

<6> B Counter Bypass Only valid when operating the prescaler in fixed divide (FD) mode. When this bit is set, the

B counter is divided by 1. This allows the prescaler setting to determine the divide for the

N divider.

0A

0B

<7>

Not Used.

<5:0> 14-Bit Reference R Divider (MSB) <13:8>.

Counter, MSBs

0C

0D

<7:0> 14-Bit Reference R Divider (MSB) <7:0>.

Counter, R LSBs

<1:0> Antibacklash

Pulse-Width

<1>

0

1

<0>

Antibacklash Pulse Width (ns)

0

1

0

1

1.3 (Default)

2.9

6.0

1.3

0D

<4:2>

Not Used.

<5> Digital Lock

Detect Window

<5>

Digital Lock Detect Window (ns) Digital Lock Detect Loss-of-Lock Threshold (ns)

0 (Default)

1

9.5

3.5

15

7

Digital Lock

Detect Window

If the time difference of the rising edges at the inputs to the PFD are less than the lock detect

window time, the digital lock detect flag is set. The flag remains set until the time difference is

greater than the loss-of-lock threshold.

0D

<6> Lock Detect

Disable

0 = Normal Lock Detect Operation (Default).

1 = Disable Lock Detect.

<7>

Not Used.

Unused

0E-33

Not Used.

Rev. A | Page 49 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

Fine Delay Adjust

Description

34

<0> Delay Control

OUT4

Delay Block Control Bit.

Bypasses Delay Block and Powers It Down (Default = 1b).

34

35

<7:1>

Not Used.

<2:0> Ramp Current

OUT4

The slowest ramp (200 ꢀs) sets the longest full scale of approximately 10 ns.

<2>

0

<1>

0

<0>

0

Ramp Current (μs)

200

0

1

400

0

1

0

600

0

1

800

1

0

1

0

1

0

1

1000

1200

1400

1600

35

<5:3> Ramp Capacitor

OUT4

Selects the Number of Capacitors in Ramp Generation Circuit.

More Capacitors => Slower Ramp.

<5>

<4>

0

<3>

0

Number of Capacitors

0

4 (Default)

0

1

0

1

0

1

0

1

0

1

0

1

3

2

3

2

1

35

36

<7:6>

<0>

Not Used.

<5:1> Delay Fine Adjust Sets Delay Within Full Scale of the Ramp; There Are 32 Steps.

OUT4

00000b => Zero Delay (Default).

11111b => Maximum Delay.

36

<7:6>

Not Used.

37 (38) (39) <7:0>

(3A) (3B)

(3C)

3D (3E) (3F) <1:0> Power-Down

LVPECL

OUT0

(OUT1)

(OUT2)

Mode

ON

PD1

PD2

<1>

<0>

Description

Output

ON

OFF

0

1

0

1

0

Normal Operation

Test Only—Do Not Use

Safe Power-Down

OFF

Partial Power-Down; Use If

Output Has Load Resistors

PD3

1

Total Power-Down

Use Only If Output Has No

Load Resistors

OFF

Rev. A | Page 50 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

Description

3D (3E) (3F) <3:2> Output Level

Output Single-Ended Voltage Levels for LVPECL Outputs.

LVPECL

OUT0

(OUT1)

(OUT2)

<3>

<2>

0

Output Voltage (mV)

0

490

0

1

330

1

0

1

805 (Default)

650

3D (3E) (3F) <7:4>

Not Used

40 (41)

<0> Power-Down

LVDS/CMOS

OUT3

Power-Down Bit for Both Output and LVDS Driver.

0 = LVDS/CMOS on (Default).

1 = LVDS/CMOS Power-Down.

(OUT4)

40 (41)

<2:1> Output Current

Level

LVDS

OUT3

(OUT4)

<2>

0

<1>

0

Current (mA)

Termination (Ω)

1.75

100

50

0

1

3.5 (Default)

1

0

5.25

7

1

50

40 (41)

<3> LVDS/CMOS

Select

0 = LVDS (Default).

1 = CMOS.

OUT3

(OUT4)

<4> Inverted CMOS

Affects Output Only when in CMOS Mode.

0 = Disable Inverted CMOS Driver (Default).

1 = Enable Inverted CMOS Driver.

Driver

OUT3

(OUT4)

<7:5>

Not Used.

42 (43) (44) <7:0>

45

<0> Clock Select

0: CLK2 Drives Distribution Section.

1: CLK1 Drives Distribution Section (Default).

45

<1> CLK1 Power-Down 1 = CLK1 Input Is Powered Down (Default = 0b).

<2> CLK2 Power-Down 1 = CLK2 Input Is Powered Down (Default = 0b).

<3> Prescaler Clock

Power-Down

1 = Shut Down Clock Signal to PLL Prescaler (Default = 0b).

45

<4> REFIN Power-

Down

1 = Power-Down REFIN (Default = 0b).

<5> All Clock Inputs

Power-Down

1 = Power-Down CLK1 and CLK2 Inputs and Associated Bias and Internal Clock Tree;

(Default = 0b).

<7:6>

<7:0>

Not Used.

46 (47)

(48) (49)

Rev. A | Page 51 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

<3:0> Divider High

OUT0

Description

Number of Clock Cycles Divider Output Stays High.

4A

(4C)

(4E)

(50)

(52)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

<7:4> Divider Low

OUT0

Number of Clock Cycles Divider Output Stays Low.

4A

(4C)

(4E)

(50)

(52)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

<3:0> Phase Offset

OUT0

Phase Offset (Default = 0000b).

4B

(4D)

(4F)

(51)

(53)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

<4> Start

OUT0

Selects Start High or Start Low.

(Default = 0b).

4B

(4D)

(4F)

(51)

(53)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

<5> Force

Forces Individual Outputs to the State Specified in Start (Above).

This Function Requires That Nosync (Below) Also Be Set (Default = 0b).

4B

OUT0

(OUT1)

(OUT2)

(OUT3)

(OUT4)

(4D)

(4F)

(51)

(53)

<6> Nosync

OUT0

Ignore Chip-Level Sync Signal (Default = 0b).

4B

(4D)

(4F)

(51)

(53)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

<7> Bypass Divider

OUT0

Bypass and Power-Down Divider Logic; Route Clock Directly to Output (Default = 0b).

4B

(4D)

(4F)

(51)

(53)

(OUT1)

(OUT2)

(OUT3)

(OUT4)

54 (55)

<7:0>

Not Used.

(56) (57)

58

<0> SYNC Detect

Enable

1 = Enable SYNC Detect (Default = 0b).

<1> SYNC Select

1 = Raise Flag if Slow Clocks Are Out-of-Sync by 0.5 to 1 High Speed Clock Cycles.

0 (Default) = Raise Flag if Slow Clocks Are Out-of-Sync by 1 to 1.5 High Speed Clock Cycles.

Rev. A | Page 52 of 60

AD9511

Reg.

Addr.

(Hex)

Bit(s) Name

Description

58

<2> Soft SYNC

Soft SYNC bit works the same as the FUNCTION pin when in SYNCB mode, except that this bit’s

polarity is reversed. That is, a high level forces selected outputs into a known state, and a high > low

transition triggers a sync (Default = 0b).

58

<3> Dist Ref Power-

Down

1 = Power-Down the References for the Distribution Section (Default = 0b).

<4> SYNC Power-

Down

1 = Power-Down the SYNC (Default = 0b).

<6:5> FUNCTION Pin

Select

<6>

<5>

0

Function

0

RESETB (Default)

SYNCB

0

1

0

Test Only; Do Not Use

PDB

1

58

59

5A

<7>

Not Used

<7:0>

<0> Update Registers 1 written to this bit updates all registers and transfers all serial control port register buffer contents

to the control registers on the next rising SCLK edge. This is a self-clearing bit. 0 does not have to be

written to clear it.

5A

<7:1>

Not Used.

END

Rev. A | Page 53 of 60

AD9511

POWER SUPPLY

The AD9511 requires a 3.3 V 5ꢀ power supply for V_S.

The tables in the Specifications section give the performance

expected from the AD9511 with the power supply voltage

within this range. The absolute maximum range of −0.3 V to

+3.6 V, with respect to GND, must never be exceeded on

the VS pin.

POWER MANAGEMENT

The power usage of the AD9511 can be managed to use only the

power required for the functions that are being used. Unused

features and circuitry can be powered down to save power. The

following circuit blocks can be powered down, or are powered

down when not selected (see the Register Map and Description

section):

Good engineering practice should be followed in the layout of

power supply traces and ground plane of the PCB. The power

supply should be bypassed on the PCB with adequate

capacitance (>10 ꢁF). The AD9511 should be bypassed with

adequate capacitors (0.1 ꢁF) at all power pins, as close as

possible to the part. The layout of the AD9511 evaluation board

(AD9511/PCB or AD9511-VCO/PCB) is a good example.

•

The PLL section can be powered down if not needed.

Any of the dividers are powered down when bypassed—

equivalent to divide-by-one.

•

The adjustable delay block on OUT4 is powered down

when not selected.

The AD9511 is a complex part that is programmed for its

desired operating configuration by on-chip registers. These

registers are not maintained over a shutdown of external power.

This means that the registers can lose their programmed values

if V_Sis lost long enough for the internal voltages to collapse.

Careful bypassing should protect the part from memory loss

under normal conditions. Nonetheless, it is important that the

V_Spower supply not become intermittent, or the AD9511 risks

losing its programming.

Any output may be powered down. However, LVPECL

outputs have both a safe and an off condition. When the

LVPECL output is terminated, only the safe shutdown

should be used to protect the LVPECL output devices. This

still consumes some power.

•

The entire distribution section can be powered down when

not needed.

Powering down a functional block does not cause the

programming information for that block (in the registers) to be

lost. This means that blocks can be powered on and off without

otherwise having to reprogram the AD9511. However,

synchronization is lost. A SYNC must be issued to

The internal bias currents of the AD9511 are set by the R_SETand

CPR_SETresistors. These resistors should be as close as possible to

the values given as conditions in the Specifications section

(R_SET= 4.12 kΩ and CPR_SET= 5.1 kΩ). These values are standard

1ꢀ resistor values and should be readily obtainable. The bias

currents set by these resistors determine the logic levels and

operating conditions of the internal blocks of the AD9511. The

performance figures given in the Specifications section assume

that these resistor values are used.

resynchronize (see the Single-Chip Synchronization section).

The VCP pin is the supply pin for the charge pump (CP). The

voltage at this pin (V_CP) may be from V_Sup to 5.5 V, as required

to match the tuning voltage range of a specific VCO/VCXO.

This voltage must never exceed the absolute maximum of 6 V.

V_CPshould also never be allowed to be less than −0.3 V below

V_Sor GND, whichever is lower.

The exposed metal paddle on the AD9511 package is an

electrical connection, as well as a thermal enhancement. For

the device to function properly, the paddle must be properly

attached to ground (GND). The PCB acts as a heat sink for the

AD9511; therefore, this GND connection should provide a

good thermal path to a larger dissipation area, such as a ground

plane on the PCB. See the layout of the AD9511 evaluation

board (AD9511/PCB or AD9511-VCO/PCB) for a good

example.

Rev. A | Page 54 of 60

AD9511

APPLICATIONS

USING THE AD9511 OUTPUTS FOR ADC CLOCK

APPLICATIONS

level, termination) should be considered when selecting the best

clocking/converter solution.

Any high speed analog-to-digital converter (ADC) is extremely

sensitive to the quality of the sampling clock provided by the

user. An ADC can be thought of as a sampling mixer; any noise,

distortion, or timing jitter on the clock is combined with the

desired signal at the A/D output. Clock integrity requirements

scale with the analog input frequency and resolution, with

higher analog input frequency applications at ≥14-bit resolution

being the most stringent. The theoretical SNR of an ADC is

limited by the ADC resolution and the jitter on the sampling

clock. Considering an ideal ADC of infinite resolution where

the step size and quantization error can be ignored, the available

SNR can be expressed approximately by

CMOS CLOCK DISTRIBUTION

The AD9511 provides two clock outputs (OUT3 and OUT4),

which are selectable as either CMOS or LVDS levels. When

selected as CMOS, these outputs provide for driving devices

requiring CMOS level logic at their clock inputs.

Whenever single-ended CMOS clocking is used, some of the

following general guidelines should be followed.

Point-to-point nets should be designed such that a driver has

one receiver only on the net, if possible. This allows for simple

termination schemes and minimizes ringing due to possible

mismatched impedances on the net. Series termination at the

source is generally required to provide transmission line

matching and/or to reduce current transients at the driver. The

value of the resistor is dependent on the board design and

timing requirements (typically 10 Ω to 100 Ω is used). CMOS

outputs are limited in terms of the capacitive load or trace

length that they can drive. Typically, trace lengths less than

3 inches are recommended to preserve signal rise/fall times and

preserve signal integrity.

⎡

⎢

⎤

⎥

1

2πft

SNR = 20×log

⎢

⎣

⎥

⎦

j

where f is the highest analog frequency being digitized, and t_jis

the rms jitter on the sampling clock. Figure 53 shows the

required sampling clock jitter as a function of the analog

frequency and effective number of bits (ENOB).

t = 50fs

j

60.4Ω

1

2πft

SNR = 20log

120

10

1.0 INCH

j

10Ω

18

16

14

12

10

8

CMOS

t = 0.1ps

j

MICROSTRIP

100

80

t = 1ps

j

50pF

GND

t = 10ps

j

Figure 54. Series Termination of CMOS Output

60

40

20

Termination at the far end of the PCB trace is a second option.

The CMOS outputs of the AD9511 do not supply enough

current to provide a full voltage swing with a low impedance

resistive, far-end termination, as shown in Figure 55. The far-

end termination network should match the PCB trace

impedance and provide the desired switching point. The

reduced signal swing can still meet receiver input requirements

in some applications. This may be useful when driving long

trace lengths on less critical nets.

t = 100ps

j

6

t = 1ns

j

4

1

3

10

30

100

FULL-SCALE SINE WAVE ANALOG INPUT FREQUENCY (MHz)

Figure 53. ENOB and SNR vs. Analog Input Frequency

See Application Notes AN-756 and AN-501 on the ADI website

at www.analog.com.

V

= 3.3V

PULLUP

Many high performance ADCs feature differential clock inputs

to simplify the task of providing the required low jitter clock on

a noisy PCB. (Distributing a single-ended clock on a noisy PCB

can result in coupled noise on the sample clock. Differential

distribution has inherent common-mode rejection, which can

provide superior clock performance in a noisy environment.)

The AD9511 features both LVPECL and LVDS outputs that

provide differential clock outputs, which enable clock solutions

that maximize converter SNR performance. The input

100Ω

50Ω

10Ω

CMOS

3pF

OUT3, OUT4

100Ω

SELECTED AS CMOS

Figure 55. CMOS Output with Far-End Termination

requirements of the ADC (differential or single-ended, logic

Rev. A | Page 55 of 60

AD9511

Because of the limitations of single-ended CMOS clocking,

consider using differential outputs when driving high speed

signals over long traces. The AD9511 offers both LVPECL and

LVDS outputs, which are better suited for driving long traces

where the inherent noise immunity of differential signaling

provides superior performance for clocking converters.

LVDS CLOCK DISTRIBUTION

Low voltage differential signaling (LVDS) is a second

differential output option for the AD9511. LVDS uses a current

mode output stage with several user-selectable current levels.

The normal value (default) for this current is 3.5 mA, which

yields 350 mV output swing across a 100 Ω resistor. The LVDS

outputs meet or exceed all ANSI/TIA/EIA—644 specifications.

LVPECL CLOCK DISTRIBUTION

The low voltage, positive emitter-coupled, logic (LVPECL)

outputs of the AD9511 provide the lowest jitter clock signals

available from the AD9511. The LVPECL outputs (because they

are open emitter) require a dc termination to bias the output

transistors. A simplified equivalent circuit in Figure 41 shows

the LVPECL output stage.

A recommended termination circuit for the LVDS outputs is

shown in Figure 58.

3.3V

100Ω

LVDS

DIFFERENTIAL (COUPLED)

In most applications, a standard LVPECL far-end termination is

recommended, as shown in Figure 56. The resistor network is

designed to match the transmission line impedance (50 Ω) and

the desired switching threshold (1.3 V).

Figure 58. LVDS Output Termination

3.3V

See Application Note AN-586 on the ADI website at

www.analog.com for more information on LVDS.

3.3V

127Ω

50Ω

POWER AND GROUNDING CONSIDERATIONS AND

POWER SUPPLY REJECTION

SINGLE-ENDED

(NOT COUPLED)

LVPECL

Many applications seek high speed and performance under less

than ideal operating conditions. In these application circuits,

the implementation and construction of the PCB is as

important as the circuit design. Proper RF techniques must be

used for device selection, placement, and routing, as well as for

power supply bypassing and grounding to ensure optimum

performance.

50Ω

83Ω

V

= V – 1.3V

CC

T

Figure 56. LVPECL Far-End Termination

3.3V

0.1nF

DIFFERENTIAL

100Ω

LVPECL

(COUPLED)

0.1nF

200Ω

Figure 57. LVPECL with Parallel Transmission Line

Rev. A | Page 56 of 60

AD9511

OUTLINE DIMENSIONS

0.30

0.23

0.18

7.00

BSC SQ

0.60 MAX

PIN 1

INDICATOR

37

36

48

1

PIN 1

INDICATOR

EXPOSED

5.25

5.10 SQ

4.95

TOP

VIEW

6.75

BSC SQ

PAD

(BOTTOM VIEW)

0.50

0.40

0.30

25

24

12

13

0.25 MIN

5.50

REF

0.80 MAX

0.65 TYP

1.00

0.85

0.80

12° MAX

0.05 MAX

0.02 NOM

COPLANARITY

0.08

0.50 BSC

0.20 REF

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MO-220-VKKD-2

Figure 59. 48-Lead Lead Frame Chip Scale Package [LFCSP_VQ]

7 mm × 7 mm Body, Very Thin Quad

(CP-48-1)

Dimensions shown in millimeters

ORDERING GUIDE

Model

AD9511BCPZ¹

AD9511BCPZ-REEL7¹

AD9511/PCB

Temperature Range

−40°C to +85°C

Package Description

Package Option

48-Lead Lead Frame Chip Scale Package (LFCSP_VQ)

Evaluation Board without VCO, VCXO, or Loop Filter

Evaluation Board with 245.76 MHz VCXO, Loop Filter

CP-48-1

AD9511-VCO/PCB

¹Z = Pb-free part.

Rev. A | Page 57 of 60

AD9511

NOTES

Rev. A | Page 58 of 60

AD9511

NOTES

Rev. A | Page 59 of 60

AD9511

NOTES

registered trademarks are the property of their respective owners.

D05286–0–6/05(A)

Rev. A | Page 60 of 60


型号：	AD9511/PCB
厂家：	ADI
描述：	1.2 GHz Clock Distribution IC, PLL Core, Dividers, Delay Adjust, Five Outputs 1.2 GHz的时钟分配IC ， PLL内核，分频器，延迟调整，五路输出时钟
文件：	总60页 (文件大小：1207K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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