MAX19706ETM-T [MAXIM]
Telecom Circuit, 1-Func, 7 X 7 MM, 0.80 MM HEIGHT, MO-220, TQFN-48;![MAX19706ETM-T](http://pdffile.icpdf.com/pdf2/p00313/img/icpdf/MAX19706ETM-_1882107_icpdf.jpg)
型号: | MAX19706ETM-T |
厂家: | ![]() |
描述: | Telecom Circuit, 1-Func, 7 X 7 MM, 0.80 MM HEIGHT, MO-220, TQFN-48 电信 电信集成电路 |
文件: | 总37页 (文件大小:1186K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
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19-3867; Rev 0; 10/05
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
General Description
Features
The MAX19706 is an ultra-low-power, mixed-signal ana-
log front-end (AFE) designed for power-sensitive com-
munication equipment. Optimized for high dynamic
performance at ultra-low power, the device integrates a
dual, 10-bit, 22Msps receive (Rx) ADC; dual, 10-bit,
22Msps transmit (Tx) DAC; three fast-settling 12-bit aux-
DAC channels for ancillary RF front-end control; and a
10-bit, 333ksps housekeeping aux-ADC. The typical
operating power in Tx-Rx FAST mode is 49.5mW at a
22MHz clock frequency.
♦ Dual, 10-Bit, 22Msps Rx ADC and Dual, 10-Bit,
22Msps Tx DAC
♦ Ultra-Low Power
49.5mW at fCLK = 22MHz, Fast Mode
39.3mW at fCLK = 22MHz, Slow Mode
Low-Current Standby and Shutdown Modes
♦ Programmable Tx DAC Common-Mode DC Level
and I/Q Offset Trim
♦ Excellent Dynamic Performance
The Rx ADCs feature 54.6dB SNR and 75.6dBc SFDR at
a 5.5MHz input frequency with a 22MHz clock frequen-
cy. The analog I/Q input amplifiers are fully differential
SNR = 54.6dB at fIN = 5.5MHz (Rx ADC)
SFDR = 72.6dBc at fOUT = 2.2MHz (Tx DAC)
♦ Three 12-Bit, 1µs Aux-DACs
and accept 1.024V
full-scale signals. Typical I/Q
P-P
channel matching is 0.12ꢀ phase and 0.01dB gain.
♦ 10-Bit, 333ksps Aux-ADC with 4:1 Input Mux and
Data Averaging Mode
The Tx DACs feature 72.6dBc SFDR at f = 2.2MHz
OUT
and f
= 22MHz. The analog I/Q full-scale output volt-
CLK
♦ Excellent Gain/Phase Match
age is 400mV differential. The Tx DAC common-mode
DC level is programmable from 0.9V to 1.35V. The I/Q
channel offset is adjustable. The typical I/Q channel
matching is 0.02dB gain and 0.1ꢀ phase.
0.12ꢀ Phase, 0.01dB Gain (Rx ADC) at
IN = 5.5MHz
f
♦ Multiplexed Parallel Digital I/O
♦ Serial-Interface Control
The Rx ADC and Tx DAC share a single, 10-bit parallel,
high-speed digital bus allowing half-duplex operation for
time-division duplex (TDD) applications. A 3-wire serial
interface controls power-management modes, the aux-
DAC channels, and the aux-ADC channels.
♦ Versatile Power-Control Circuits
Shutdown, Standby, Idle, Tx/Rx Disable
♦ Miniature 48-Pin Thin QFN Package
(7mm x 7mm x 0.8mm)
The MAX19706 operates on a single +2.7V to +3.3V ana-
log supply and +1.8V to +3.3V digital I/O supply. The
MAX19706 is specified for the extended (-40ꢀC to +85ꢀC)
temperature range and is available in a 48-pin, thin QFN
package. The Selector Guide at the end of the data sheet
lists other pin-compatible versions in this AFE family.
Pin Configuration
TOP VIEW
36 35 34 33
31 30 29 28 27 26 25
32
24
23
22
21
20
19
18
Applications
and Wi-Bro CPEs
37
DAC2
D9
D8
D7
D6
OV
DAC1 38
39
(SM)
WiMAX
V
DD
IDN 40
IDP 41
802.11a/b/g WLAN
DD
VoIP Terminals
GND
42
43
OGND
D5
Portable Communication Equipment
V
DD
MAX19706
17 D4
QDN 44
QDP 45
REFIN 46
16
WiMAX is a service mark of Bandwidth.com, Inc.
D3
EXPOSED PADDLE (GND)
15
D2
COM
47
14 D1
13 D0
Ordering Information
REFN 48
PART*
PIN-PACKAGE
48 Thin QFN-EP**
48 Thin QFN-EP**
PKG CODE
1
2
3
4
6
7
8
9
10 11 12
5
MAX19706ETM
MAX19706ETM+
T4877-4
T4877-4
*All devices are specified over the -40°C to +85°C operating
range.
THIN QFN
**EP = Exposed paddle.
+Denotes lead-free package.
Functional Diagram and Selector Guide appear at end of
data sheet.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ABSOLUTE MAXIMUM RATINGS
V
to GND, OV
to OGND ..............................-0.3V to +3.6V
DD
Continuous Power Dissipation (T = +70ꢀC)
A
DD
GND to OGND.......................................................-0.3V to +0.3V
IAP, IAN, QAP, QAN, IDP, IDN, QDP,
48-Pin Thin QFN (derate 27.8mW/ꢀC above +70ꢀC) .....2.22W
Thermal Resistance θ ..................................................36ꢀC/W
JA
QDN, DAC1, DAC2, DAC3 to GND......................-0.3V to V
Operating Temperature Range ...........................-40ꢀC to +85ꢀC
Junction Temperature......................................................+150ꢀC
Storage Temperature Range.............................-60ꢀC to +150ꢀC
Lead Temperature (soldering, 10s) .................................+300ꢀC
DD
ADC1, ADC2 to GND .................................-0.3V to (V
REFP, REFN, REFIN, COM to GND............-0.3V to (V
D0–D9, DOUT, T/R, SHDN, SCLK, DIN, CS,
+ 0.3V)
+ 0.3V)
DD
DD
CLK to OGND......................................-0.3V to (OV
+ 0.3V)
DD
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER REQUIREMENTS
Analog Supply Voltage
Output Supply Voltage
V
2.7
1.8
3.0
3.3
V
V
DD
OV
V
DD
DD
Ext1-Tx, Ext3-Tx, and SPI2-Tx states;
transmit DAC operating mode (Tx):
f
= 22MHz, f
= 2.2MHz on both
11.3
16.5
15.6
13.1
CLK
OUT
channels; aux-DACs ON and at midscale,
aux-ADC ON
Ext2-Tx, Ext4-Tx, and SPI4-Tx states;
transmit DAC operating mode (Tx):
f
= 22MHz, f
= 2.2MHz on both
20
19
CLK
OUT
channels; aux-DACs ON and at midscale,
aux-ADC ON
V
Supply Current
mA
DD
Ext1-Rx, Ext4-Rx, and SPI3-Rx states;
receive ADC operating mode (Rx):
f
= 22MHz, f = 5.5MHz on both
IN
CLK
channels; aux-DACs ON and at midscale,
aux-ADC ON
Ext2-Rx, Ext3-Rx, and SPI1-Rx states;
receive ADC operating mode (Rx):
f
= 22MHz, f = 5.5MHz on both
IN
CLK
channels; aux-DACs ON and at midscale,
aux-ADC ON
2
_______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
mA
Standby mode: CLK = 0 or OV
aux-DACs ON and at midscale,
aux-ADC ON
;
DD
3
5
V
Supply Current
DD
Idle mode: f
= 22MHz; aux-DACs ON
CLK
8
12
and at midscale, aux-ADC ON
Shutdown mode: CLK = 0 or OV
0.8
µA
DD
Ext1-Rx, Ext2-Rx, Ext3-Rx, Ext4-Rx,
SPI1-Rx, SPI3-Rx states; receive ADC
operating mode (Rx): f
= 22MHz,
CLK
4.8
mA
f
IN
= 5.5MHz on both channels;
aux-DACs ON and at midscale,
aux-ADC ON
Ext1-Tx, Ext2-Tx, Ext3-Tx, Ext4-Tx,
SPI2-Tx, SPI4-Tx states; transmit DAC
OV
Supply Current
DD
operating mode (Tx): f
= 22MHz, f
247
0.7
CLK
OUT
= 2.2MHz on both channels; aux-DACs
ON and at midscale, aux-ADC ON
µA
Standby mode: CLK = 0 or OV ; aux-
DD
DACs ON and at midscale, aux-ADC ON
Idle mode: f
and at midscale, aux-ADC ON
= 22MHz; aux-DACs ON
CLK
37.8
0.7
Shutdown mode: CLK = 0 or OV
DD
Rx ADC DC ACCURACY
Resolution
N
10
Bits
LSB
Integral Nonlinearity
Differential Nonlinearity
Offset Error
INL
DNL
0.9
0.45
1
LSB
Residual DC offset error
Include reference error
-5
-5
+5
+5
%FS
%FS
dB
Gain Error
0.85
DC Gain Matching
Offset Matching
-0.15
0.001 +0.15
7.4
17
LSB
Gain Temperature Coefficient
ppm/ꢀC
LSB
Offset error (V
5%)
5%)
2
DD
Power-Supply Rejection
PSRR
Gain error (V
0.06
%FS
DD
_______________________________________________________________________________________
3
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Rx ADC ANALOG INPUT
Input Differential Range
V
Differential or single-ended inputs
0.512
V
V
ID
Input Common-Mode Voltage
Range
V
V
/ 2
DD
CM
R
Switched capacitor load
245
5
kΩ
IN
Input Impedance
C
pF
IN
Rx ADC CONVERSION RATE
Maximum Clock Frequency
f
(Note 2)
22
MHz
CLK
Channel I
Channel Q
5
Clock
Cycles
Data Latency (Figure 3)
5.5
Rx ADC DYNAMIC CHARACTERISTICS (Note 3)
f
f
f
f
f
f
f
f
= 5.5MHz, f
= 22MHz
= 22MHz
= 22MHz
= 22MHz
= 22MHz
= 22MHz
= 22MHz
= 22MHz
53
52.9
64
54.6
54.5
54.6
54.4
75.6
76.3
IN
IN
IN
IN
IN
IN
IN
IN
CLK
Signal-to-Noise Ratio
SNR
SINAD
SFDR
HD3
dB
= 13MHz, f
CLK
= 5.5MHz, f
CLK
CLK
Signal-to-Noise and Distortion
Spurious-Free Dynamic Range
Third-Harmonic Distortion
Intermodulation Distortion
dB
= 13MHz, f
= 5.5MHz, f
CLK
CLK
dBc
dBc
dBc
dBc
dBc
= 13MHz, f
= 5.5MHz, f
-78.7
-77.9
CLK
CLK
= 13MHz, f
f = 1.8MHz, -7dBFS;
1
IMD
-70
f = 1.0MHz, -7dBFS
2
Third-Order Intermodulation
Distortion
f = 1.8MHz, -7dBFS;
1
f = 1.0MHz, -7dBFS
2
IM3
-76.7
f
f
= 5.5MHz, f
= 22MHz
= 22MHz
-72.4
-73.5
3.5
-63
IN
CLK
Total Harmonic Distortion
THD
= 13MHz, f
IN
CLK
Aperture Delay
ns
ns
Overdrive Recovery Time
1.5x full-scale input
2
Rx ADC INTERCHANNEL CHARACTERISTICS
f
= 5.5MHz at -0.5dBFS, f
= 1MHz at
INX,Y
INX,Y
Crosstalk Rejection
-90
dB
dB
-0.5dBFS (Note 4)
Amplitude Matching
Phase Matching
f
IN
= 5.5MHz at -0.5dBFS (Note 5)
= 5.5MHz at -0.5dBFS (Note 5)
0.01
0.12
f
IN
Degrees
4
_______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Tx DAC DC ACCURACY
Resolution
N
10
0.39
0.2
1
Bits
LSB
LSB
Integral Nonlinearity
Differential Nonlinearity
INL
DNL
Guaranteed monotonic (Note 6)
-1
-4
+1
+4
T
> +25ꢀC
< +25ꢀC
A
A
Residual DC Offset
Full-Scale Gain Error
V
mV
mV
OS
T
-5
1
+5
T
T
> +25ꢀC
< +25ꢀC
-30
-40
+30
+40
A
Include reference error
(peak-to-peak error)
A
Tx DAC DYNAMIC PERFORMANCE
DAC Conversion Rate
f
(Note 2)
22
MHz
CLK
In-Band Noise Density
N
f
= 2.2MHz, f = 22MHz
CLK
-130.1
84
dBc/Hz
D
OUT
Third-Order Intermodulation
Distortion
IM3
f = 2MHz, f = 2.2MHz
1
dBc
pV•s
dBc
2
Glitch Impulse
10
Spurious-Free Dynamic Range to
Nyquist
SFDR
f
= 22MHz, f
= 2.2MHz
61
72.6
CLK
OUT
Total Harmonic Distortion to
Nyquist
THD
SNR
f
f
= 22MHz, f
= 22MHz, f
= 2.2MHz
= 2.2MHz
-70.2
59.7
-60
dB
dB
CLK
CLK
OUT
Signal-to-Noise Ratio to Nyquist
OUT
Tx DAC INTERCHANNEL CHARACTERISTICS
I-to-Q Output Isolation
f
= 2MHz, f
= 2.2MHz
90
dB
dB
OUTX,Y
OUTX,Y
T
T
> +25ꢀC
< +25ꢀC
-0.3
0.02
+0.3
A
Gain Mismatch Between DAC
Outputs
Measured at DC
-0.38
+0.38
A
Phase Mismatch Between DAC
Outputs
f
= 2.2MHz, f
= 45MHz
0.1
Degrees
OUT
CLK
Differential Output Impedance
800
Ω
Tx DAC ANALOG OUTPUT
Full-Scale Output Voltage
V
400
1.35
1.2
mV
V
FS
Bits CM1 = 0, CM0 = 0 (default)
Bits CM1 = 0, CM0 = 1
Bits CM1 = 1, CM0 = 0
Bits CM1 = 1, CM0 = 1
1.29
1.41
Output Common-Mode Voltage
V
COM
1.05
0.9
_______________________________________________________________________________________
5
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Rx ADC–Tx DAC INTERCHANNEL CHARACTERISTICS
Rx ADC f = f
= 5.5MHz, Tx DAC
INI
INQ
Receive Transmit Isolation
85
dB
f
= f
OUTQ
= 2.2MHz, f
= 22MHz
OUTI
CLK
AUXILIARY ADC (ADC1, ADC2)
Resolution
N
10
Bits
V
AD1 = 0 (default)
AD1 = 1
2.048
Full-Scale Reference
V
REF
V
DD
0 to
Analog Input Range
V
V
REF
Analog Input Impedance
Input-Leakage Current
At DC
500
kΩ
µA
Measured at unselected input from 0 to
0.1
V
REF
Gain Error
GE
ZE
Includes reference error
-5
+5
%FS
mV
Zero-Code Error
Differential Nonlinearity
Integral Nonlinearity
Supply Current
2
DNL
INL
0.53
0.45
210
LSB
LSB
µA
AUXILIARY DACs (DAC1, DAC2, DAC3)
Resolution
N
12
Bits
Integral Nonlinearity
INL
1.25
LSB
Guaranteed monotonic over codes 100 to
4000 (Note 6)
Differential Nonlinearity
DNL
-1.0
0.65
+1.2
0.1
LSB
Gain Error
GE
ZE
R > 200kΩ
L
0.7
0.6
%FS
%FS
V
Zero-Code Error
Output-Voltage Low
Output-Voltage High
DC Output Impedance
Settling Time
R > 200kΩ
L
V
OL
V
R > 200kΩ
L
2.56
V
OH
DC output at midscale
4
1
Ω
From 1/4 FS to 3/4 FS, within 10 LSB
From 0 to FS transition
µs
Glitch Impulse
24
nV•s
Rx ADC–Tx DAC TIMING CHARACTERISTICS
CLK Rise to Channel-I Output Data
Valid
t
Figure 3 (Note 6)
Figure 3 (Note 6)
Figure 5 (Note 6)
4.8
6.6
10
6.6
8.8
8.5
ns
ns
ns
DOI
CLK Fall to Channel-Q Output
Data Valid
t
11.1
DOQ
I-DAC DATA to CLK Fall Setup
Time
t
DSI
6
_______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
Figure 5 (Note 6)
MIN
TYP
MAX
UNITS
ns
Q-DAC DATA to CLK Rise Setup
Time
t
10
0
DSQ
CLK Fall to I-DAC Data Hold Time
t
Figure 5 (Note 6)
Figure 5 (Note 6)
ns
DHI
CLK Rise to Q-DAC Data Hold
Time
t
0
ns
DHQ
CLK Duty Cycle
50
15
%
%
ns
CLK Duty-Cycle Variation
Digital Output Rise/Fall Time
20% to 80%
2.6
SERIAL-INTERFACE TIMING CHARACTERISTICS (Figure 6, Note 6)
Falling Edge of CS to Rising Edge
of First SCLK Time
t
10
ns
CSS
DIN to SCLK Setup Time
DIN to SCLK Hold Time
SCLK Pulse-Width High
SCLK Pulse-Width Low
SCLK Period
t
10
0
ns
ns
ns
ns
ns
ns
ns
ns
DS
DH
CH
t
t
25
25
50
10
80
t
CL
CP
CS
t
t
SCLK to CS Setup Time
CS High Pulse Width
CS High to DOUT Active High
t
CSW
t
Bit AD0 set
200
4.36
200
200
CSD
Bit AD0 set, no averaging (see Table 14),
CS High to DOUT Low (Aux-ADC
Conversion Time)
t
f
= 22MHz,
µs
CONV
CLK
CLK divider = 8 (see Table 15)
DOUT Low to CS Setup Time
SCLK Low to DOUT Data Out
CS High to DOUT High Impedance
t
t
Bit AD0, AD10 set
Bit AD0, AD10 set
Bit AD0, AD10 set
ns
ns
ns
DCS
t
14.5
CD
CHZ
MODE-RECOVERY TIMING CHARACTERISTICS (Figure 7)
From shutdown to Rx mode, ADC settles
to within 1dB SINAD
82.2
26.4
9.6
Shutdown Wake-Up Time
Idle Wake-Up Time (With CLK)
Standby Wake-Up Time
t
µs
µs
µs
WAKE,SD
From shutdown to Tx mode, DAC settles to
within 10 LSB error
From idle to Rx mode with CLK present
during idle, ADC settles to within 1dB SINAD
t
WAKE,ST0
WAKE,ST1
From idle to Tx mode with CLK present
during idle, DAC settles to 10 LSB error
6.0
From standby to Rx mode, ADC settles to
within 1dB SINAD
17.5
22
t
From standby to Tx mode, DAC settles to
10 LSB error
_______________________________________________________________________________________
7
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Enable Time from Tx to Rx (Ext2-Tx
to Ext2-Rx, Ext4-Tx to Ext4-Rx, and
SPI4-Tx to SPI3-Rx States)
t
ADC settles to within 1dB SINAD
500
ns
ENABLE, RX
Enable Time from Rx to Tx (Ext1-Rx
to Ext1-Tx, Ext4-Rx to Ext4-Tx, and
SPI3-Rx to SPI4-Tx States)
t
DAC settles to within 10 LSB error
ADC settles to within 1dB SINAD
DAC settles to within 10 LSB error
500
8.1
6.0
ns
µs
µs
ENABLE, TX
Enable Time from Tx to Rx (Ext1-Tx
to Ext1-Rx, Ext3-Tx to Ext3-Rx, and
SPI1-Tx to SPI2-Rx States)
t
ENABLE, RX
Enable Time from Rx to Tx (Ext2-Rx
to Ext2-Tx, Ext3-Rx to Ext3-Tx, and
SPI1-Rx to SPI2-Tx States)
t
ENABLE, TX
INTERNAL REFERENCE (V
Positive Reference
= V ; V
, V
, V
levels are generated internally)
REFIN
DD REFP REFN COM
V
V
- V
0.256
V
V
REFP
REFN
COM
Negative Reference
- V
-0.256
COM
V
/ 2
V
/ 2
DD
DD
Common-Mode Output Voltage
V
V
/ 2
V
COM
DD
2
- 0.15
+ 0.15
Maximum REFP/REFN/COM
Source Current
I
mA
SOURCE
Maximum REFP/REFN/COM
Sink Current
I
2
mA
V
SINK
Differential Reference Output
V
V
- V
REFN
+0.490 +0.512 +0.534
12
REF
REFP
Differential Reference Temperature
Coefficient
REFTC
ppm/ꢀC
BUFFERED EXTERNAL REFERENCE (external V
= 1.024V applied; V
, V
, V
levels are generated internally)
REFIN
REFP REFN COM
Reference Input Voltage
V
1.024
0.512
V
V
V
REFIN
Differential Reference Output
Common-Mode Output Voltage
V
V
- V
REFP REFN
DIFF
V
V
/ 2
COM
DD
Maximum REFP/REFN/COM
Source Current
I
2
mA
mA
SOURCE
Maximum REFP/REFN/COM
Sink Current
I
2
SINK
REFIN Input Current
-0.7
500
µA
REFIN Input Resistance
kΩ
8
_______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ELECTRICAL CHARACTERISTICS (continued)
(V
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFN
REFP
C
COM
= 0.33µF, unless otherwise noted. C < 5pF on all aux-DAC outputs. Typical values are at T = +25ꢀC.) (Note 1)
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DIGITAL INPUTS (CLK, SCLK, DIN, CS, D0–D9, T/R, SHDN)
Input High Threshold
Input Low Threshold
V
0.7 x OV
V
V
INH
DD
V
0.3 x OV
DD
INL
D0–D9, CLK, SCLK, DIN, CS, T/R,
Input Leakage
DI
-1
+1
µA
pF
IN
SHDN = OGND or OV
DD
Input Capacitance
DC
5
5
IN
DIGITAL OUTPUTS (D0–D9, DOUT)
Output-Voltage Low
V
I
I
= 200µA
0.2 x OV
DD
V
V
OL
SINK
Output-Voltage High
V
= 200µA
0.8 x OV
-1
OH
SOURCE
DD
Tri-State Leakage Current
Tri-State Output Capacitance
I
+1
µA
pF
LEAK
C
OUT
Note 1: Specifications from T = +25ꢀC to +85ꢀC are guaranteed by production tests. Specifications from T = +25ꢀC to -40ꢀC are
A
A
guaranteed by design and characterization.
Note 2: The minimum clock frequency (f ) for the MAX19706 is 2MHz (typ). The minimum aux-ADC sample rate clock frequency
CLK
(ACLK) is determined by f
and the chosen aux-ADC clock-divider value. The minimum aux-ADC ACLK > 2MHz / 128
CLK
TM
= 15.6kHz. The aux-ADC conversion time does not include the time to clock the serial data out of the SPI . The maximum
conversion time (for no averaging, NAVG = 1) will be t
(max) = (12 x 1 x 128) / 2MHz = 768µs.
CONV
Note 3: SNR, SINAD, SFDR, HD3, and THD are based on a differential analog input voltage of -0.5dBFS referenced to the amplitude
of the digital outputs. SINAD and THD are calculated using HD2 through HD6.
Note 4: Crosstalk rejection is measured by applying a high-frequency test tone to one channel and a low-frequency tone to the second
channel. FFTs are performed on each channel. The parameter is specified as the power ratio of the first and second channel
FFT test tone.
Note 5: Amplitude and phase matching is measured by applying the same signal to each channel, and comparing the two output
signals using a sine-wave fit.
Note 6: Guaranteed by design and characterization.
SPI is a trademark of Motorola, Inc.
Typical Operating Characteristics
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
Rx ADC CHANNEL-IA
TWO-TONE FFT PLOT
Rx ADC CHANNEL-IA FFT PLOT
Rx ADC CHANNEL-QA FFT PLOT
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
0
0
f
= 22MHz
f
f
A
= 22MHz
= 5.468363MHz
= -0.5dB
8192-POINT
DATA RECORD
f
f
A
= 22MHz
CLK
CLK
IA
IA
CLK
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
f = 1.8MHz
= 5.468363MHz
= -0.5dB
8192-POINT
1
QA
QA
f = 2.1MHz
2
A
= -7dBFS
IA
PER TONE
8192-POINT
DATA RECORD
DATA RECORD
0
1
2
3
4
5
6
7
8
9 10
0
1
2
3
4
5
6
7
8
9 10
0
1
2
3
4
5
6
7
8
9 10
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
_______________________________________________________________________________________
9
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Typical Operating Characteristics (continued)
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
Rx ADC CHANNEL-QA
TWO-TONE FFT PLOT
56.0
Rx ADC SIGNAL-TO-NOISE RATIO
vs. ANALOG INPUT FREQUENCY
Rx ADC SIGNAL-TO-NOISE AND DISTORTION
RATIO vs. ANALOG INPUT FREQUENCY
56.0
0
f
= 22MHz
CLK
55.5
55.0
54.5
54.0
53.5
53.0
52.5
52.0
51.5
51.0
50.5
50.0
55.5
55.0
54.5
54.0
53.5
53.0
52.5
52.0
51.5
51.0
50.5
50.0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
f = 1.8MHz
1
IA
IA
f = 2.1MHz
2
A
= -7dBFS
QA
PER TONE
8192-POINT
DATA RECORD
QA
QA
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
0
1
2
3
4
5
6
7
8
9 10
FREQUENCY (MHz)
Rx ADC SIGNAL-TO-NOISE RATIO
vs. ANALOG INPUT AMPLITUDE
Rx ADC TOTAL HARMONIC DISTORTION
vs. ANALOG INPUT FREQUENCY
Rx ADC SPURIOUS-FREE DYNAMIC RANGE
vs. ANALOG INPUT FREQUENCY
60
58
56
54
52
50
48
46
44
42
40
38
36
34
32
30
-60
82
80
78
76
74
72
70
68
66
64
62
60
f
= 5.468363MHz
IN
-62
-64
-66
-68
-70
-72
-74
-76
-78
-80
QA
IA
QA
IA
IA
QA
-21 -18 -15 -12
-9
-6
-3
0
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
0
10 20 30 40 50 60 70 80 90 100
ANALOG INPUT FREQUENCY (MHz)
ANALOG INPUT AMPLITUDE (dBFS)
Rx ADC TOTAL HARMONIC DISTORTION
vs. ANALOG INPUT AMPLITUDE
Rx ADC SPURIOUS-FREE DYNAMIC RANGE
vs. ANALOG INPUT AMPLITUDE
Rx ADC SIGNAL-TO-NOISE AND DISTORTION
RATIO vs. ANALOG INPUT AMPLITUDE
-50
-55
85
80
75
70
65
60
55
50
60
58
56
54
52
50
f
= 5.468363MHz
f
= 5.468363MHz
IN
f
= 5.468363MHz
IN
IN
QA
-60
-65
-70
-75
-80
-85
QA
QA
48
46
44
42
40
38
36
34
32
30
IA
IA
IA
-21 -18 -15 -12
-9
-6
-3
0
-21 -18 -15 -12
-9
-6
-3
0
-21 -18 -15 -12
-9
-6
-3
0
ANALOG INPUT AMPLITUDE (dBFS)
ANALOG INPUT AMPLITUDE (dBFS)
ANALOG INPUT AMPLITUDE (dBFS)
10 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Typical Operating Characteristics (continued)
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
Rx ADC SIGNAL-TO-NOISE AND DISTORTION
Rx ADC SIGNAL-TO-NOISE RATIO
vs. SAMPLING RATE
Rx ADC TOTAL HARMONIC DISTORTION
vs. SAMPLING RATE
RATIO vs. SAMPLING RATE
56.0
55.5
55.0
54.5
54.0
53.5
53.0
56.0
55.5
55.0
54.5
54.0
53.5
53.0
-70
-71
-72
-73
-74
-75
-76
-77
-78
-79
-80
f
= 5.468363MHz
f = 5.468363MHz
IN
IN
f
= 5.468363MHz
IN
QA
QA
IA
IA
IA
QA
1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5
SAMPLING RATE (MHz)
1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5
SAMPLING RATE (MHz)
1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5
SAMPLING RATE (MHz)
Rx ADC SIGNAL-TO-NOISE AND DISTORTION
RATIO vs. CLOCK DUTY CYCLE
Rx ADC SPURIOUS-FREE DYNAMIC RANGE
vs. SAMPLING RATE
Rx ADC SIGNAL-TO-NOISE RATIO
vs. CLOCK DUTY CYCLE
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
56.0
55.5
55.0
54.5
54.0
53.5
53.0
52.5
52.0
51.5
51.0
50.5
50.0
56.0
55.5
55.0
54.5
54.0
53.5
53.0
52.5
52.0
51.5
51.0
50.5
50.0
f
= 5.468363MHz
f
= 5.468363MHz
f = 5.468363MHz
IN
IN
IN
QA
QA
IA
IA
QA
IA
1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5
SAMPLING RATE (MHz)
35
40
45
50
55
60
65
35
40
45
50
55
60
65
CLOCK DUTY CYCLE (%)
CLOCK DUTY CYCLE (%)
Rx ADC TOTAL HARMONIC DISTORTION
vs. CLOCK DUTY CYCLE
Rx ADC OFFSET ERROR
vs. TEMPERATURE
Rx ADC SPURIOUS-FREE DYNAMIC RANGE
vs. CLOCK DUTY CYCLE
-70
-71
-72
-73
-74
-75
-76
-77
-78
-79
-80
-81
-82
-83
-84
-85
0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-1.4
-1.6
-1.8
-2.0
85
84
83
82
81
80
f
= 5.468363MHz
IN
IA
f
= 5.468363MHz
IN
IA
79
78
77
76
75
74
73
72
71
70
QA
QA
IA
QA
35
40
45
50
55
60
65
-40 -25 -10
5
20 35 50 65 80
35
40
45
50
55
60
65
CLOCK DUTY CYCLE (%)
TEMPERATURE (°C)
CLOCK DUTY CYCLE (%)
______________________________________________________________________________________ 11
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Typical Operating Characteristics (continued)
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
Tx DAC SPURIOUS-FREE DYNAMIC
RANGE vs. SAMPLING RATE
Rx ADC GAIN ERROR
vs. TEMPERATURE
85
Tx DAC SPURIOUS-FREE DYNAMIC
RANGE vs. OUTPUT FREQUENCY
2.0
1.8
1.6
1.4
1.2
1.0
0.8
1.6
0.4
0.2
0
85
82
79
76
73
70
f
= f / 10
OUT CLK
QA
81
77
73
69
65
IA
2
4
6
8
10 12 14 16 18 20 22
-40 -25 -10
5
20 35 50 65 80
0
1
2
3
4
5
6
7
8
9 10 11
SAMPLING RATE (MHz)
TEMPERATURE (°C)
OUTPUT FREQUENCY (MHz)
Tx DAC SPURIOUS-FREE DYNAMIC
RANGE vs. OUTPUT AMPLITUDE
Tx DAC CHANNEL-ID SPECTRAL PLOT
Tx DAC CHANNEL-QD SPECTRAL PLOT
90
80
70
60
50
40
30
0
0
f
= 2.2MHz
f = 2.2MHz
ID
f
= 2.2MHz
OUT
QD
-10
-20
-30
-40
-50
-60
-70
-80
-90
-10
-20
-30
-40
-50
-60
-70
-80
-90
-30
-25
-20
-15
-10
-5
0
1
2
3
4
5
6
7
8
9
10 11
1
2
3
4
5
6
7
8
9
10 11
OUTPUT AMPLITUDE (dBFS)
FREQUENCY (MHz)
FREQUENCY (MHz)
Tx DAC CHANNEL-ID TWO-TONE
SPECTRAL PLOT
Tx DAC CHANNEL-QD TWO-TONE
SPECTRAL PLOT
SUPPLY CURRENT
vs. SAMPLING RATE
16
14
12
10
8
0
-10
-20
0
-10
-20
f = 4MHz,
1
f = 4.5MHz
2
Ext4-Tx MODE
f = 4MHz,
1
f = 4.5MHz
2
I
VDD
f
1
f
1
-30
-40
-50
-60
-30
-40
-50
-60
-70
f
2
f
2
6
4
-70
-80
2
0
-80
2
4
6
8
10 12 14 16 18 20 22
2
3
4
5
6
7
8
9
10 11
2
3
4
5
6
7
8
9
10 11
SAMPLING RATE (MHz)
FREQUENCY (MHz)
FREQUENCY (MHz)
12 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Typical Operating Characteristics (continued)
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
Rx ADC INTEGRAL NONLINEARITY
Rx ADC DIFFERENTIAL NONLINEARITY
Tx DAC INTEGRAL NONLINEARITY
1.0
0.8
1.0
1.0
0.8
0.8
0.6
0.6
0.6
0.4
0.4
0.4
0.2
0.2
0.2
0
0
0
-0.2
-0.4
-0.6
-0.8
-1.0
-0.2
-0.4
-0.6
-0.8
-1.0
-0.2
-0.4
-0.6
-0.8
-1.0
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
0
128 256 384 512 640 768 896 1024
DIGITAL INPUT CODE
REFERENCE OUTPUT VOLTAGE
vs. TEMPERATURE
AUX-DAC OUTPUT VOLTAGE
vs. OUTPUT SOURCE CURRENT
Tx DAC DIFFERENTIAL NONLINEARITY
0.5
0.4
0.520
0.515
0.510
0.505
0.500
3.0
2.5
2.0
1.5
1.0
0.5
0
V
- V
REFN
REFP
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
0
128 256 384 512 640 768 896 1024
DIGITAL INPUT CODE
-40
-15
10
35
60
85
0.001
0.01
0.1
1
10
100
TEMPERATURE (°C)
OUTPUT SOURCE CURRENT (mA)
______________________________________________________________________________________ 13
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Typical Operating Characteristics (continued)
(V
DD
= 3V, OV
= 1.8V, internal reference (1.024V), C ≈ 10pF on all digital outputs, f
= 22MHz (50% duty cycle), Rx ADC input
DD
L
CLK
amplitude = -0.5dBFS, Tx DAC output amplitude = 0dBFS, differential Rx ADC input, differential Tx DAC output, C
= C
=
REFP
REFN
C
COM
= 0.33µF, T = +25ꢀC, unless otherwise noted.)
A
AUX-DAC OUTPUT VOLTAGE
vs. OUTPUT SINK CURRENT
AUX-DAC INTEGRAL NONLINEARITY
AUX-DAC SETTLING TIME
2.0
1.5
1.0
0.5
0
3.0
2.5
2.0
1.5
1.0
0.5
0
STEP FROM 1/4FS TO 3/4FS
500mV/div
-0.5
-1.0
-1.5
-2.0
0
1024
2048
3072
4096
0.001
0.01
0.1
1
10
100
500ns/div
DIGITAL INPUT CODE
OUTPUT SINK CURRENT (mA)
AUX-ADC DIFFERENTIAL NONLINEARITY
AUX-DAC DIFFERENTIAL NONLINEARITY
AUX-ADC INTEGRAL NONLINEARITY
0.8
0.4
0
0.8
0.6
0.4
0.2
0
2.0
1.5
1.0
0.5
0
-0.2
-0.4
-0.6
-0.8
-0.5
-1.0
-1.5
-2.0
-0.4
-0.8
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
0
1024
2048
3072
4096
0
128 256 384 512 640 768 896 1024
DIGITAL OUTPUT CODE
DIGITAL INPUT CODE
Pin Description
PIN
NAME
FUNCTION
1
REFP
Upper Reference Voltage. Bypass with a 0.33µF capacitor to GND as close to REFP as possible.
2, 8, 11, 31,
33, 39, 43
Analog Supply Voltage. Bypass V
a 0.1µF capacitor.
to GND with a combination of a 2.2µF capacitor in parallel with
DD
V
DD
3
IAP
IAN
Channel-IA Positive Analog Input. For single-ended operation, connect signal source to IAP.
Channel-IA Negative Analog Input. For single-ended operation, connect IAN to COM.
Analog Ground. Connect all GND pins to ground plane.
4
5, 7, 12, 32, 42
GND
CLK
QAN
6
9
Conversion Clock Input. Clock signal for both receive ADCs and transmit DACs.
Channel-QA Negative Analog Input. For single-ended operation, connect QAN to COM.
14 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Pin Description (continued)
PIN
NAME
FUNCTION
10
QAP
Channel-QA Positive Analog Input. For single-ended operation, connect signal source to QAP.
Digital I/O. Outputs for receive ADC in Rx mode. Inputs for transmit DAC in Tx mode. D9 is the most
significant bit (MSB) and D0 is the least significant bit (LSB).
13–18, 21–24
D0–D9
OGND
19
20
Output-Driver Ground
Output-Driver Power Supply. Supply range from +1.8V to V . Bypass OV
DD
to OGND with a
DD
OV
DD
combination of a 2.2µF capacitor in parallel with a 0.1µF capacitor.
25
26
SHDN
Active-Low Shutdown Input. Apply logic-low to place the MAX19706 in shutdown.
Aux-ADC Digital Output
DOUT
Transmit/Receive-Mode Select Input. T/R logic-low input sets the device in receive mode. A logic-
high input sets the device in transmit mode. If modes are set through SPI commands, the T/R input
27
T/R
must be pulled up to OV or pulled down to OGND.
DD
28
29
DIN
SCLK
CS
3-Wire Serial-Interface Data Input. Data is latched on the rising edge of the SCLK.
3-Wire Serial-Interface Clock Input
30
3-Wire Serial-Interface Chip-Select Input. Logic-low enables the serial interface.
Auxiliary ADC Analog Input
34
ADC2
ADC1
DAC3
DAC2
DAC1
IDN, IDP
35
Auxiliary ADC Analog Input
36
Auxiliary DAC3 Analog Output
37
Auxiliary DAC2 Analog Output
38
Auxiliary DAC1 Analog Output (AFC DAC, V
DAC Channel-ID Differential Voltage Output
= 1.1V During Power-Up)
OUT
40, 41
44, 45
46
QDN, QDP DAC Channel-QD Differential Voltage Output
REFIN
COM
Reference Input. Connect to V
for internal reference.
DD
47
Common-Mode Voltage I/O. Bypass COM to GND with a 0.33µF capacitor.
Negative Reference I/O. Rx ADC conversion range is (V
0.1µF capacitor.
- V
). Bypass REFN to GND with a
REFP
REFN
48
—
REFN
EP
Exposed Paddle. Exposed paddle is internally connected to GND. Connect EP to the GND plane.
automatic frequency-control (AFC) level setting. The
Detailed Description
aux-ADC features data averaging to reduce processor
overhead and a selectable clock-divider to program the
conversion rate.
The MAX19706 integrates a dual, 10-bit Rx ADC and a
dual, 10-bit Tx DAC while providing ultra-low power
and high dynamic performance at a 22Msps conver-
sion rate. The Rx ADC analog input amplifiers are fully
The MAX19706 includes a 3-wire serial interface to
control operating modes and power management. The
serial interface is SPI and MICROWIRE™ compatible.
The MAX19706 serial interface selects shutdown, idle,
standby, transmit (Tx), and receive (Rx) modes, as well
as controls aux-DAC and aux-ADC channels.
differential and accept 1.024V
full-scale signals. The
P-P
Tx DAC analog outputs are fully differential with
400mV full-scale output, selectable common-mode
DC level, and adjustable I/Q offset trim.
The MAX19706 integrates three 12-bit auxiliary DAC
(aux-DAC) channels and a 10-bit, 333ksps auxiliary
ADC (aux-ADC) with 4:1 input multiplexer. The aux-DAC
channels feature 1µs settling time for fast automatic
gain-control (AGC), variable-gain amplifier (VGA), and
The Rx ADC and Tx DAC share a common digital I/O to
reduce the digital interface to a single, 10-bit parallel
multiplexed bus. The 10-bit digital bus operates on a
single +1.8V to +3.3V supply.
MICROWIRE is a trademark of National Semiconductor Corp.
______________________________________________________________________________________ 15
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
V
is the difference between V
and V
. See
Dual, 10-Bit Rx ADC
The ADC uses a seven-stage, fully differential, pipelined
architecture that allows for high-speed conversion while
minimizing power consumption. Samples taken at the
inputs move progressively through the pipeline stages
every half clock cycle. Including the delay through the
output latch, the total clock-cycle latency is 5 clock
cycles for channel IA and 5.5 clock cycles for channel
REF
REFP
REFN
the Reference Configurations section for details.
Input Track-and-Hold (T/H) Circuits
Figure 1 displays a simplified diagram of the Rx ADC
input track-and-hold (T/H) circuitry. Both ADC inputs
(IAP, QAP, IAN, and QAN) can be driven either differen-
tially or single-ended. Match the impedance of IAP and
IAN, as well as QAP and QAN, and set the input signal
QA. The ADC full-scale analog input range is
V
REF
common-mode voltage within the V / 2 ( 200mV)
DD
Rx ADC range for optimum performance.
with a V / 2 ( 200mV) common-mode input range.
DD
INTERNAL
BIAS
COM
S5a
S2a
C1a
S3a
S4a
S4b
IAP
IAN
OUT
OUT
C2a
C2b
S4c
S1
C1b
S3b
S5b
COM
S2b
CLK
INTERNAL
NONOVERLAPPING
CLOCK SIGNALS
HOLD
HOLD
INTERNAL
BIAS
TRACK
TRACK
INTERNAL
BIAS
COM
S5a
S2a
C1a
S3a
S4a
S4b
QAP
QAN
OUT
OUT
C2a
C2b
S4c
S1
MAX19706
C1b
S3b
S5b
COM
S2b
INTERNAL
BIAS
Figure 1. Rx ADC Internal T/H Circuits
16 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 1. Rx ADC Output Codes vs. Input Voltage
DIFFERENTIAL INPUT
VOLTAGE
DIFFERENTIAL INPUT (LSB)
OFFSET BINARY (D0–D9)
OUTPUT DECIMAL CODE
V
V
x 512/512
x 511/512
511 (+Full Scale - 1 LSB)
510 (+Full Scale - 2 LSB)
+1
11 1111 1111
11 1111 1110
10 0000 0001
10 0000 0000
01 1111 1111
00 0000 0001
00 0000 0000
1023
1022
513
512
511
1
REF
REF
V
V
x 1/512
x 0/512
x 1/512
REF
REF
0 (Bipolar Zero)
-1
-V
REF
-V
x 511/512
x 512/512
-511 (-Full Scale +1 LSB)
-512 (-Full Scale)
REF
REF
-V
0
multiplexed at the D0–D9 outputs. CHI data is updated
on the rising edge and CHQ data is updated on the
falling edge of the CLK. Including the delay through the
output latch, the total clock-cycle latency is 5 clock
cycles for CHI and 5.5 clock cycles for CHQ.
2 x V
REF
V
= V
- V
1 LSB =
REF
REFP REFN
1024
V
V
REF
REF
11 1111 1111
11 1111 1110
11 1111 1101
Digital Input/Output Data (D0–D9)
D0–D9 are the Rx ADC digital logic outputs when the
MAX19706 is in receive mode. This bus is shared with
the Tx DAC digital logic inputs and operates in half-
duplex mode. D0–D9 are the Tx DAC digital logic inputs
when the MAX19706 is in transmit mode. The logic level
10 0000 0001
10 0000 0000
01 1111 1111
(COM)
is set by OV
from 1.8V to V . The digital output cod-
DD
DD
ing is offset binary (Table 1). Keep the capacitive load
on the digital outputs D0–D9 as low as possible (< 15pF)
to avoid large digital currents feeding back into the ana-
log portion of the MAX19706 and degrading its dynamic
performance. Buffers on the digital outputs isolate the
outputs from heavy capacitive loads. Adding 100Ω resis-
tors in series with the digital outputs close to the
MAX19706 will help improve Rx ADC and Tx DAC per-
formance. Refer to the MAX19707EVKIT schematic for
an example of the digital outputs driving a digital buffer
through 100Ω series resistors.
00 0000 0011
00 0000 0010
00 0000 0001
00 0000 0000
-1
1
+512
+509 +510 +511
-512 -511 -510 -509
0+
(COM)
INPUT VOLTAGE (LSB)
Figure 2. Rx ADC Transfer Function
During SHDN, IDLE, and STBY states, D0–D9 are inter-
nally pulled up to prevent floating digital inputs. To
ensure no current flows through D0–D9 I/O, the external
Rx ADC System Timing Requirements
Figure 3 shows the relationship between the clock, ana-
log inputs, and the resulting output data. Channel I
(CHI) and channel Q (CHQ) are sampled on the rising
edge of the clock signal (CLK) and the resulting data is
bus needs to be either tri-stated or pulled up to OV
Do not pull the external bus to ground.
.
DD
______________________________________________________________________________________ 17
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
5.5 CLOCK-CYCLE LATENCY (CHQ)
5 CLOCK-CYCLE LATENCY (CHI)
CHI
CHQ
t
CLK
t
t
CH
CL
CLK
t
DOQ
t
DOI
D0–D9
D0Q
D1I
D1Q
D2I
D2Q
D3I
D3Q
D4I
D4Q
D5I
D5Q
D6I
D6Q
Figure 3. Rx ADC System Timing Diagram
analog interface between RF quadrature upconverters
and the MAX19706. Many RF upconverters require a
0.9V to 1.35V common-mode bias. The Tx DAC DC
common-mode bias eliminates discrete level-setting
resistors and code-generated level shifting while pre-
serving the full dynamic range of each Tx DAC. The Tx
DAC differential analog outputs cannot be used in sin-
gle-ended mode because of the internally generated
common-mode DC level. Table 2 shows the Tx DAC
output voltage vs. input codes. Table 10 shows the
selection of DC common-mode levels. See Figure 4 for
an illustration of the Tx DAC analog output levels.
Dual, 10-Bit Tx DAC
The dual, 10-bit digital-to-analog converter (Tx DAC)
operates with clock speeds up to 22MHz. The Tx DAC
digital inputs, D0–D9, are multiplexed on a single 10-bit
bus. The voltage reference determines the Tx DAC full-
scale output voltage. See the Reference Configurations
section for details on setting the reference voltage.
The Tx DAC outputs at IDN, IDP and QDN, QDP are
biased at a 0.9V to 1.35V adjustable DC common-
mode bias and designed to drive a differential input
stage with ≥ 70kΩ input impedance. This simplifies the
Table 2. Tx DAC Output Voltage vs. Input Codes
(Internal Reference Mode V
= 1.024V, External Reference Mode V
= V ; V = 400 for 800mV
REFIN FS P-P
REFDAC
REFDAC
Full Scale)
DIFFERENTIAL OUTPUT VOLTAGE (V)
OFFSET BINARY (D0–D9)
INPUT DECIMAL CODE
V
1023
1023
REFDAC
1024
V
×
(
)
11 1111 1111
1023
FS
V
1021
1023
REFDAC
)
1024
V
×
(
11 1111 1110
10 0000 0001
10 0000 0000
01 1111 1111
00 0000 0001
00 0000 0000
1022
513
512
511
1
FS
V
3
1023
REFDAC
1024
V
×
×
×
(
)
)
FS
V
1
1023
REFDAC
1024
V
(
FS
−V
REFDAC
1
1023
V
(
)
FS
1024
−V
1021
1023
1023
REFDAC
1024
V
×
(
)
FS
−V
REFDAC
1024
V
×
(
)
0
FS
1023
18 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
The Tx DAC also features independent DC offset cor-
rection of each I/Q channel. This feature is configured
through the SPI interface. The DC offset correction is
used to optimize sideband and carrier suppression in
the Tx signal path (see Table 9).
MAX19706
EXAMPLE:
Tx DAC
I-CH
Tx RFIC INPUT REQUIREMENTS
• DC COMMON-MODE BIAS =
1.2V (MIN), 1.5V (MAX)
0
90
• BASEBAND INPUT = 400mV
DC-COUPLED
Tx DAC
Q-CH
FULL SCALE = 1.55V
COMMON-MODE LEVEL
SELECT CM1 = 0, CM0 = 0
V
COM
= 1.35V
V
V
= 1.35V
COM
DIFF
=
400mV
ZERO SCALE = 1.15V
0V
Figure 4. Tx DAC Common-Mode DC Level at IDN, IDP or QDN, QDP Differential Outputs
______________________________________________________________________________________ 19
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Tx DAC Timing
Figure 5 shows the relationship between the clock, input
data, and analog outputs. Data for the I channel (ID) is
latched on the falling edge of the clock signal, and Q-
channel (QD) data is latched on the rising edge of the
clock signal. Both I and Q outputs are simultaneously
updated on the next rising edge of the clock signal.
composed of A3–A0 control bits and D11–D0 data bits.
Data is shifted in MSB first (D11) and LSB last (A0).
Tables 4, 5, and 6 show the MAX19706 operating
modes and SPI commands. The serial interface remains
active in all modes.
SPI Register Description
Program the control bits, A3–A0, in the register as shown
in Table 3 to select the operating mode. Modify A3–A0
bits to select from ENABLE-16, Aux-DAC1, Aux-DAC2,
Aux-DAC3, IOFFSET, QOFFSET, Aux-ADC, ENABLE-8,
and COMSEL modes. ENABLE-16 is the default operat-
ing mode. This mode allows for shutdown, idle, and
standby states as well as switching between FAST,
SLOW, Rx, and Tx modes. Table 4 shows the MAX19706
power-management modes. Table 5 shows the T/R pin-
controlled external Tx-Rx switching modes. Table 6
shows the SPI-controlled Tx-Rx switching modes.
3-Wire Serial Interface and
Operation Modes
The 3-wire serial interface controls the MAX19706 oper-
ation modes as well as the three 12-bit aux-DACs and
the 10-bit aux-ADC. Upon power-up, program the
MAX19706 to operate in the desired mode. Use the 3-
wire serial interface to program the device for shut-
down, idle, standby, Rx, Tx, aux-DAC controls, or
aux-ADC conversion. A 16-bit data register sets the
mode control as shown in Table 3. The 16-bit word is
CLK
t
t
DHQ
DSQ
Q: N - 2
I: N - 1
Q: N - 1
Q: N
I: N + 1
D0–D9
I: N
t
t
DHI
DSI
N - 2
N - 2
ID
N - 1
N - 1
N
N
QD
Figure 5. Tx DAC System Timing Diagram
20 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 3. MAX19706 Mode Control
D11
D10
15
D9
14
D8
13
D7
12
D6
11
D5
10
D4
9
D3
8
D2
7
D1
6
D0 A3 A2 A1
A0
REGISTER
NAME
(MSB)
5
4
3
2
1 (LSB)
E11 = 0
Reserved Reserved
E10 = 0
ENABLE-16
E9
—
—
E6
E5
E4
E3
E2
E1
E0
0
0
0
0
Aux-DAC1
Aux-DAC2
Aux-DAC3
IOFFSET
1D11
2D11
3D11
—
1D10
2D10
3D10
—
1D9 1D8 1D7 1D6 1D5 1D4 1D3 1D2 1D1 1D0
2D9 2D8 2D7 2D6 2D5 2D4 2D3 2D2 2D1 2D0
3D9 3D8 3D7 3D6 3D5 3D4 3D3 3D2 3D1 3D0
0
0
0
0
0
0
0
0
0
1
1
1
0
1
1
0
0
1
1
0
1
0
1
0
—
—
—
—
—
—
—
—
—
—
—
—
IO5 IO4 IO3 IO2 IO1 IO0
QO5 QO4 QO3 QO2 QO1 QO0
QOFFSET
COMSEL
—
—
—
—
—
—
—
—
CM1 CM0
AD11 = 0
Reserved
Aux-ADC
AD10
—
AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
0
1
1
0
1
0
1
0
ENABLE-8
—
—
—
—
—
—
—
E3
E2
E1
E0
— = Not used.
Table 4. Power-Management Modes
ADDRESS
DATA BITS
T/R
FUNCTION
(POWER
MODE
DESCRIPTION
COMMENT
MANAGEMENT)
A3 A2 A1 A0 E9* E3 E2 E1 E0 PIN 27
Rx ADC = OFF
Tx DAC = OFF
Aux-DAC = OFF
Aux-ADC = OFF
CLK = OFF
Device is in complete
shutdown.
Overrides T/R pin.
1X000
XX001
1X010
X
X
X
SHDN
SHUTDOWN
REF = OFF
0000
(16-Bit Mode)
or
1000
(8-Bit Mode)
Rx ADC = OFF
Tx DAC = OFF
Aux-DAC = Last State Moderate idle power.
CLK = ON
REF = ON
Fast turn-on time.
IDLE
IDLE
Overrides T/R pin.
Rx ADC = OFF
Tx DAC = OFF
Aux-DAC = Last State
Aux-ADC = OFF
CLK = OFF
Slow turn-on time.
Low standby power.
Overrides T/R pin.
STBY
STANDBY
REF = ON
X = Don’t care.
*Bit E9 is not available in 8-bit mode.
______________________________________________________________________________________ 21
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 5. External Tx-Rx Control Using T/R Pin (T/R = 0 = Rx Mode, T/R = 1 = Tx Mode)
FUNCTION
Rx TO Tx-Tx TO Rx
ADDRESS
DATA BITS
T/R
STATE
DESCRIPTION
COMMENT
SWITCHING SPEED
A3 A2 A1 A0 E3 E2 E1 E0 PIN 27
Rx Mode:
Moderate Power:
Fast Rx to Tx when T/R
transitions 0 to 1.
Rx ADC = ON
Tx DAC = ON
Rx Bus = Enable
0
Ext1-Rx
0011
FAST-SLOW
SLOW-FAST
SLOW-SLOW
FAST-FAST
Tx Mode:
Low Power:
Slow Tx to Rx when T/R
transitions 1 to 0.
Rx ADC = OFF
Tx DAC = ON
Tx Bus = Enable
1
Ext1-Tx
Rx Mode:
Low Power:
Slow Rx to Tx when T/R
transitions 0 to 1.
Ext2-Rx
(Default)
Rx ADC = ON
Tx DAC = OFF
Rx Bus = Enable
0
0100
Tx Mode:
Moderate Power:
Rx ADC = ON
Tx DAC = ON
Tx Bus = Enable
Fast Tx to Rx when T/R
transitions 1 to 0.
1
Ext2-Tx
Ext3-Rx
Ext3-Tx
Ext4-Rx
Ext4-Tx
0000
(16-Bit Mode)
or
Rx Mode:
1000
(8-Bit Mode)
Low Power:
Slow Rx to Tx when T/R
transitions 0 to 1.
Rx ADC = ON
Tx DAC = OFF
Rx Bus = Enable
0
0101
Tx Mode:
Low Power:
Slow Tx to Rx when T/R
transitions 1 to 0.
Rx ADC = OFF
Tx DAC = ON
Tx Bus = Enable
1
Rx Mode:
Moderate Power:
Fast Rx to Tx when T/R
transitions 0 to 1.
Rx ADC = ON
Tx DAC = ON
Rx Bus = Enable
0
0110
Tx Mode:
Moderate Power:
Fast Tx to Rx when T/R
transitions 1 to 0.
Rx ADC = ON
Tx DAC = ON
Tx Bus = Enable
1
22 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 6. Tx-Rx Control Using SPI Commands
FUNCTION
(Tx-Rx SWITCHING
SPEED)
ADDRESS
DATA BITS
T/R
MODE
DESCRIPTION
COMMENTS
A3 A2 A1 A0 E3 E2 E1 E0 PIN 27
Rx Mode:
Low Power:
Slow Rx to Tx through
SPI command.
Rx ADC = ON
Tx DAC = OFF
Rx Bus = Enable
1011
1100
1101
1110
X
X
X
X
SPI1-Rx
SLOW
SLOW
FAST
FAST
Tx Mode:
Low Power:
Slow Tx to Rx through
SPI command.
Rx ADC = OFF
Tx DAC = ON
Tx Bus = Enable
SPI2-Tx
SPI3-Rx
SPI4-Tx
0000
(16-Bit Mode)
or
1000
(8-Bit Mode)
Rx Mode:
Moderate Power:
Fast Rx to Tx through
SPI command.
Rx ADC = ON
Tx DAC = ON
Rx Bus = Enabled
Tx Mode:
Moderate Power:
Fast Tx to Rx through
SPI command.
Rx ADC = ON
Tx DAC = ON
Tx Bus = Enabled
X = Don’t care.
In ENABLE-16 mode, the aux-DACs have independent
control bits E4, E5, and E6, and bit E9 enables the aux-
ADC. Table 7 shows the auxiliary DAC enable codes
and Table 8 shows the auxiliary ADC enable codes. Bits
E11 and E10 are reserved. Program bits E11 and E10 to
logic-low.
Table 7. Aux-DAC Enable Table
(ENABLE-16 Mode)
E6 E5
E4
AUX-DAC3
AUX-DAC2
AUX-DAC1
ON
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
ON
ON
1
ON
ON
OFF
Modes aux-DAC1, aux-DAC2, and aux-DAC3 select
the aux-DAC channels named DAC1, DAC2, and
DAC3 and hold the data inputs for each DAC. Bits
_D11–_D0 are the data inputs for each aux-DAC and
can be programmed through SPI. The MAX19706 also
includes two 6-bit registers that can be programmed to
adjust the offsets for the Tx DAC I and Q channels
independently (see Table 9). Use the COMSEL mode
to select the output common-mode voltage with bits
CM1 and CM0 (see Table 10). Use aux-ADC mode to
start the auxiliary ADC conversion (see the 10-Bit,
333ksps Auxiliary ADC section for details). Use
ENABLE-8 mode for faster enable and switching
between shutdown, idle, and standby states as well as
switching between FAST, SLOW, and Rx and Tx
modes.
0
ON
OFF
ON
1
ON
OFF
OFF
0
OFF
ON
ON
1
OFF
ON
OFF
0
OFF
OFF
ON
1
OFF
OFF
OFF
Table 8. Aux-ADC Enable Table
(ENABLE-16 Mode)
E9
0 (Default)
1
SELECTION
Aux-ADC is Powered ON
Aux-ADC is Powered OFF
______________________________________________________________________________________ 23
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 9. Offset Control Bits for I and Q Channels (IOFFSET or QOFFSET Mode)
BITS IO5–IO0 WHEN IN IOFFSET MODE, BITS QO5–QO0 WHEN IN QOFFSET MODE
OFFSET 1 LSB =
(VFS / 1023)
P-P
IO5/QO5
IO4/QO4
IO3/QO3
IO2/QO2
IO1/QO1
IO0/QO0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
0
1
-31 LSB
-30 LSB
-29 LSB
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
1
0
0
1
0
-2 LSB
-1 LSB
0mV
0mV (Default)
1 LSB
2 LSB
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
0
0
0
1
1
1
1
1
1
1
1
1
0
1
1
1
0
1
29 LSB
30 LSB
31 LSB
Note: For transmit full scale of 400mꢀV 1 LSB = ꢁ800mꢀ
/ 1023) = 0.7820mꢀ.
P-P
time is 9.6µs to enter Rx mode and 6.0µs to enter Tx
mode. When the Rx ADC outputs transition from tri-
state to ON, the last converted word is placed on the
digital outputs.
Table 10. Common-Mode Select
(COMSEL Mode)
CM1
CM0
Tx DAC OUTPUT COMMON MODE (V)
In standby mode, the reference is powered, but the rest
of the device functions are off. The wake-up time from
standby mode is 17.5µs to enter Rx mode and 22µs to
enter Tx mode. When the Rx ADC outputs transition from
tri-state to active, the last converted word is placed on
the digital outputs.
0
0
1
1
0
1
0
1
1.35 (Default)
1.20
1.05
0.90
Shutdown mode offers the most dramatic power sav-
ings by shutting down all the analog sections of the
MAX19706 and placing the Rx ADC digital outputs in
tri-state mode. When the Rx ADC outputs transition
from tri-state to ON, the last converted word is placed
on the digital outputs. The Tx DAC previously stored
data is lost when coming out of shutdown mode. The
wake-up time from shutdown mode is dominated by the
time required to charge the capacitors at REFP, REFN,
and COM. In internal reference mode and buffered
external reference mode, the wake-up time is typically
82.2µs to enter Rx mode and 26.4µs to enter Tx mode.
FAST and SLOW Rx and Tx Modes
In addition to the external Tx-Rx control, the MAX19706
also features SLOW and FAST modes for switching
between Rx and Tx operation. In FAST Tx mode, the Rx
ADC core is powered on but the ADC core digital out-
puts are tri-stated on the D0–D9 bus; likewise, in FAST
Rx mode, the transmit DAC core is powered on but the
DAC core digital inputs are tri-stated on the D0–D9 bus.
The switching time between Tx to Rx or Rx to Tx is FAST
because the converters are on and do not have to
recover from a power-down state. In FAST mode, the
switching time between Rx to Tx and Tx to Rx is 0.5µs.
Power consumption is higher in FAST mode because
both the Tx and Rx cores are always on. To prevent
In idle mode, the reference and clock distribution cir-
cuits are powered, but all other functions are off. The
Rx ADC outputs are forced to tri-state. The wake-up
24 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
bus contention in these states, the Rx ADC output
buffers are tri-stated during Tx and the Tx DAC input
bus is tri-stated during Rx.
Tx-Rx control, program the MAX19706 through the serial
interface. During SHDN, IDLE, or STBY modes, the T/R
input is overridden. To restore external Tx-Rx control,
program bit E3 low and exit the SHDN, IDLE, or STBY
modes through the serial interface.
In SLOW mode, the Rx ADC core is off during Tx; likewise
the Tx DAC is turned off during Rx to yield lower power
consumption in these modes. For example, the power in
SLOW Tx mode is 33.9mW. The power consumption dur-
ing Rx is 39.3mW compared to 46.8mW power consump-
tion in FAST mode. However, the recovery time between
states is increased. The switching time in SLOW mode
between Rx to Tx is 6µs and Tx to Rx is 8.1µs.
When using SPI commands exclusively to control Tx-Rx
states (external T/R pin is not used), then the T/R pin
must be pulled up to OV
or pulled down to OGND.
DD
SPI Timing
The serial digital interface is a standard 3-wire connec-
tion compatible with SPI/QSPI™/MICROWIRE/DSP inter-
faces. Set CS low to enable the serial data loading at
DIN or output at DOUT. Following a CS high-to-low tran-
sition, data is shifted synchronously, most significant bit
first, on the rising edge of the serial clock (SCLK). After
16 bits are loaded into the serial input register, data is
transferred to the latch when CS transitions high. CS
must transition high for a minimum of 80ns before the
next write sequence. The SCLK can idle either high or
low between transitions. Figure 6 shows the detailed
timing diagram of the 3-wire serial interface.
External T/R Switching Control vs.
Serial-Interface Control
Bit E3 in the ENABLE-16 or ENABLE-8 register deter-
mines whether the device Tx-Rx mode is controlled
externally through the T/R input (E3 = low) or through the
SPI command (E3 = high). By default, the MAX19706 is
in the external Tx-Rx control mode. In the external control
mode, use the T/R input (pin 27) to switch between Rx
and Tx modes. Using the T/R pin provides faster switch-
ing between Rx and Tx modes. To override the external
QSPI is a trademark of Motorola, Inc.
16-BIT OR 8-BIT WRITE INTO SPI (DIN)
16-BIT OR 8-BIT WRITE
INTO SPI DURING
10-BIT READ OUT OF AUX-ADC (DOUT) WITH
SIMULTANEOUS 16-BIT WRITE INTO SPI (DIN)
AUX-ADC CONVERSION
t
CSS
t
CP
t
CS
CS
t
CSW
t
CONV
t
CL
t
t
CHZ
DCS
t
CSD
t
CH
t
DS
SCLK
t
CD
t
DH
MSB
BIT D11
(DIN)
MSB
D11 (16-BIT)
D3 (8-BIT)
LSB
BIT A0
(DIN)
D10 (16-BIT)
D2 (8-BIT)
LSB
A0
BIT D10
(DIN)
BIT D1
(DIN)
DIN
MSB
LSB
AUX-ADC
IS BUSY
DOUT
TRI-
STATED
BIT AD0
CLEARED
LSB
MSB
BIT D9
(DOUT)
LSB
BIT D0
(HELD)
DOUT = TRI-STATED WHEN
AUX-ADC IS IDLE
DOUT = ACTIVE WHEN
BIT AD0 IS SET
DOUT
BIT D0
AUX-ADC
DATA READY
(DOUT)
Figure 6. Serial-Interface Timing Diagram
______________________________________________________________________________________ 25
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
the rising and falling edges of the external clock, use a
Mode-Recovery Timing
clock with low jitter and fast rise and fall times (< 2ns).
Specifically, sampling occurs on the rising edge of the
clock signal, requiring this edge to provide the lowest
possible jitter. Any significant clock jitter limits the SNR
performance of the on-chip Rx ADC as follows:
Figure 7 shows the mode-recovery timing diagram.
WAKE
t
is the wakeup time when exiting shutdown, idle,
or standby mode and entering Rx or Tx mode. t
ENABLE
is the recovery time when switching between either Rx
or Tx mode. t or t is the time for the Rx ADC
WAKE
ENABLE
to settle within 1dB of specified SINAD performance and
Tx DAC settling to 10 LSB error. t and t
times are measured after either the 16-bit serial com-
mand is latched into the MAX19706 by a CS transition
high (SPI controlled) or a T/R logic transition (external
Tx-Rx control). In FAST mode, the recovery time is 0.5µs
to switch between Tx or Rx modes.
WAKE
ENABLE
⎛
⎞
1
SNR= 20 × log
⎜
⎟
2 × π × f × t
⎝
⎠
IN
AJ
where f represents the analog input frequency and
IN
t
AJ
is the time of the clock jitter.
Clock jitter is especially critical for undersampling
applications. Consider the clock input as an analog
input and route away from any analog input or other
digital signal lines. The MAX19706 clock input operates
System Clock Input (CLK)
Both the Rx ADC and Tx DAC share the CLK input. The
CLK input accepts a CMOS-compatible signal level set
with an OV
/ 2 voltage threshold and accepts a 50%
by OV
from 1.8V to V . Since the interstage con-
DD
DD
DD
15% duty cycle.
version of the device depends on the repeatability of
CS
SCLK
DIN
16-BIT SERIAL DATA INPUT
ADC DIGITAL OUTPUT
SINAD SETTLES WITHIN 1dB
D0–D9
ID/QD
t
TO Rx MODE OR t
,
ENABLE RX
WAKE, SD, ST_
DAC ANALOG OUTPUT
OUTPUT SETTLES TO 10 LSB ERROR
t
TO Tx MODE OR t
,
ENABLE TX
WAKE, SD, ST_
t
,
EXTERNAL T/R CONTROL
ENABLE TX
T/R
Rx - > Tx
t
,
EXTERNAL T/R CONTROL
ENABLE RX
T/R
Tx - > Rx
Figure 7. Mode-Recovery Timing Diagram
26 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
determines the internal reference of the auxiliary ADC
(see Table 12). Bits AD2 and AD3 determine the auxil-
iary ADC input source (see Table 13). Bits AD4, AD5,
and AD6 select the number of averages taken when a
single start-convert command is given. The conversion
time increases as the number of averages increases
(see Table 14). The conversion clock can be divided
down from the system clock by properly setting bits
AD7, AD8, and AD9 (see Table 15). The aux-ADC out-
put data can be written out of DOUT by setting bit
AD10 high (see Table 16).
12-Bit Auxiliary Control DACs
The MAX19706 includes three 12-bit aux-DACs (DAC1,
DAC2, DAC3) with 1µs settling time for controlling VGA,
AGC, and AFC functions. The aux-DAC output range is
0.1V to 2.56V. During power-up, the VGA and AGC out-
puts (DAC2 and DAC3) are at zero. The AFC DAC
(DAC1) is at 1.1V during power-up. The aux-DACs can
be independently controlled through the SPI bus,
except during SHDN mode where the aux-DACs are
turned off completely and the output voltage is set to
zero. In STBY and IDLE modes, the aux-DACs maintain
the last value. On wakeup from SHDN, the aux-DACs
resume the last values.
The aux-ADC features a 4:1 input multiplexer to allow
measurements on four input sources. The input sources
are selected by AD3 and AD2 (see Table 13). Two of
the multiplexer inputs (ADC1 and ADC2) can be con-
nected to external sources such as an RF power detec-
tor like the MAX2208 or temperature sensor like the
MAX6613. The other two multiplexer inputs are internal
Loading on the aux-DAC outputs should be carefully
observed to achieve specified settling time and stabili-
ty. The capacitive load must be kept to a maximum of
5pF including package and trace capacitance. The
resistive load must be greater than 200kΩ. If capacitive
loading exceeds 5pF, then add a 10kΩ resistor in
series with the output. Adding the series resistor helps
drive larger load capacitance (< 15pF) at the expense
of slower settling time.
connections to V
and OV
that monitor the power-
DD
DD
supply voltages. The internal V
and OV
connec-
DD
DD
tions are made through integrated resistor-dividers that
yield V / 2 and OV / 2 measurement results. The
DD
DD
aux-ADC voltage reference can be selected between
10-Bit, 333ksps Auxiliary ADC
The MAX19706 integrates a 10-bit, 333ksps aux-ADC
with an input 4:1 multiplexer. In the aux-ADC mode reg-
ister, setting bit AD0 begins a conversion with the auxil-
iary ADC. Bit AD0 automatically clears when the
conversion is complete. Setting or clearing AD0 during
a conversion has no effect (see Table 11). Bit AD1
an internal 2.048V bandgap reference or V (see
DD
Table 12). The V
reference selection is provided to
DD
allow measurement of an external voltage source with a
full-scale range extending beyond the 2.048V level. The
input source voltage range cannot extend above V
.
DD
Table 13. Auxiliary ADC Input Source
Table 11. Auxiliary ADC Convert
AD3
AD2
AUX-ADC INPUT SOURCE
AD0
SELECTION
0
0
1
1
0
1
0
1
ADC1 (Default)
ADC2
0
1
Aux-ADC Idle (Default)
Aux-ADC Start-Convert
V
/ 2
DD
OV
/ 2
DD
Table 12. Auxiliary ADC Reference
AD1
SELECTION
0
1
Internal 2.048V Reference (Default)
Internal V
Reference
DD
______________________________________________________________________________________ 27
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
The conversion requires 12 clock edges (1 for input
Table 14. Auxiliary ADC Averaging
sampling, 1 for each of the 10 bits, and 1 at the end for
loading into the serial output register) to complete one
conversion cycle (when no averaging is being done).
Each conversion of an average (when averaging is set
greater than 1) requires 12 clock edges. The conver-
sion clock is generated from the system clock input
(CLK). An SPI-programmable divider divides the sys-
tem clock by the appropriate divisor (set with bits AD7,
AD8, and AD9; see Table 15) and provides the conver-
sion clock to the auxiliary ADC. The auxiliary ADC has a
maximum conversion rate of 333ksps. The maximum
conversion clock frequency is 4MHz (333ksps x 12
clocks). Choose the proper divider value to keep the
conversion clock frequency under 4MHz, based upon
the system CLK frequency supplied to the MAX19706
AD6 AD5 AD4
AUX-ADC AVERAGING
1 Conversion (No Averaging) (Default)
Average of 2 Conversions
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
X
Average of 4 Conversions
Average of 8 Conversions
Average of 16 Conversions
Average of 32 Conversions
Average of 32 Conversions
X = Don’t care.
Table 15. Auxiliary ADC Clock (CLK)
Divider
(see Table 15). The total conversion time (t
) of the
CONV
auxiliary ADC can be calculated as t
= (12 x
CONV
N
x N
) / f
; where N
is the number of
AVG
DIV
CLK
AVG
AD9
0
AD8
0
AD7
0
AUX-ADC CONVERSION CLOCK
CLK Divided by 1 (Default)
CLK Divided by 2
averages (see Table 14), N
is the CLK divisor (see
DIV
Table 15), and f
is the system CLK frequency.
CLK
0
0
1
DOUT is normally in a tri-state condition. Upon setting
the auxiliary ADC start conversion bit (bit AD0), DOUT
becomes active and goes high, indicating that the aux-
ADC is busy. When the conversion cycle is complete
(including averaging), the data is placed into an output
register and DOUT goes low, indicating that the output
data is ready to be driven onto DOUT. When bit AD10 is
set (AD10 = 1), the aux-ADC enters a data output mode
where data is available on DOUT upon the next asser-
tion low of CS. The auxiliary ADC data is shifted out of
DOUT (MSB first) with the data transitioning on the
falling edge of the serial clock (SCLK). DOUT enters a
tri-state condition when CS is deasserted high. When bit
AD10 is cleared (AD10 = 0), the aux-ADC data is not
available on DOUT (see Table 16).
0
1
0
CLK Divided by 4
0
1
1
CLK Divided by 8
1
0
0
CLK Divided by 16
1
0
1
CLK Divided by 32
1
1
0
CLK Divided by 64
1
1
1
CLK Divided by 128
Table 16. Auxiliary ADC Data Output
Mode
AD10
SELECTION
0
Aux-ADC Data is Not Available on DOUT (Default)
DIN can be written independent of DOUT state. A 16-
bit instruction at DIN updates the device configuration.
To prevent modifying internal registers while reading
data from DOUT, hold DIN at a high state. This effec-
tively writes all ones into address 1111. Since address
1111 does not exist, no internal registers are affected.
Aux-ADC Enters Data Output Mode Where
Data is Available on DOUT
1
28 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Table 17. Reference Modes
V
REFIN
REFERENCE MODE
Internal Reference Mode. V
with a 0.33µF capacitor.
is internally generated to be 0.512V. Bypass REFP, REFN, and COM each
REF
> 0.8V x V
DD
Buffered External Reference Mode. An external 1.024V 10% reference voltage is applied to REFIN. V
is
REF
1.024V 10%
internally generated to be V
/ 2. Bypass REFP, REFN, and COM each with a 0.33µF capacitor. Bypass
REFIN
REFIN to GND with a 0.1µF capacitor.
Reference Configurations
25Ω
The MAX19706 features an internal precision 1.024V
bandgap reference that is stable over the entire power-
supply and temperature ranges. The REFIN input pro-
vides two modes of reference operation. The voltage at
IAP
0.1µF
22pF
V
IN
REFIN (V
) sets the reference operation mode
REFIN
(Table 17).
COM
0.33µF
0.1µF
In internal reference mode, connect REFIN to V
REF
REFP, and REFN are low-impedance outputs with
.
DD
V
is an internally generated 0.512V 4%. COM,
IAN
V
V
= V
= V
/ 2, V
/ 2 - V
= V
/ 2 + V
/ 2, and
REF
COM
REFN
DD
DD
REFP
DD
25Ω
25Ω
22pF
22pF
/ 2. Bypass REFP, REFN, and
REF
COM each with a 0.33µF capacitor. Bypass REFIN to
GND with a 0.1µF capacitor.
MAX19706
QAP
In buffered external reference mode, apply 1.024V
10% at REFIN. In this mode, COM, REFP, and REFN
0.1µF
V
IN
are low-impedance outputs with V
= V
/ 2,
COM
REFN
DD
V
V
= V
/ 2 + V / 4, and V
REFIN
= V
/ 2 -
REFP
REFIN
DD
DD
/ 4. Bypass REFP, REFN, and COM each with a
0.33µF
0.1µF
0.33µF capacitor. Bypass REFIN to GND with a 0.1µF
capacitor. In this mode, the Tx DAC full-scale output is
proportional to the external reference. For example, if
QAN
the V
is increased by 10% (max), the Tx DAC full-
REFIN
25Ω
22pF
scale output is also increased by 10% or 440mV.
Applications Information
Using Balun Transformer AC-Coupling
An RF transformer (Figure 8) provides an excellent
solution to convert a single-ended signal source to a
fully differential signal for optimum ADC performance.
Connecting the center tap of the transformer to COM
Figure 8. Balun Transformer-Coupled Single-Ended-to-
Differential Input Drive for Rx ADC
especially for high input frequencies. In differential
mode, even-order harmonics are lower as both inputs
(IAP, IAN, QAP, QAN) are balanced, and each of the
Rx ADC inputs only requires half the signal swing com-
pared to single-ended mode. Figure 9 shows an RF
transformer converting the MAX19706 Tx DAC differen-
tial analog outputs to single-ended.
provides a V
/ 2 DC level shift to the input. A 1:1
DD
transformer can be used, or a step-up transformer can
be selected to reduce the drive requirements. In gener-
al, the MAX19706 provides better SFDR and THD with
fully differential input signals than single-ended signals,
______________________________________________________________________________________ 29
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Using Op-Amp Coupling
Drive the MAX19706 Rx ADC with op amps when a
balun transformer is not available. Figures 10 and 11
show the Rx ADC being driven by op amps for AC-cou-
pled single-ended and DC-coupled differential applica-
tions. Amplifiers such as the MAX4454 and MAX4354
provide high speed, high bandwidth, low noise, and
low distortion to maintain the input signal integrity. The
op-amp circuit shown in Figure 11 can also be used to
interface with the Tx DAC differential analog outputs to
provide gain or buffering. The Tx DAC differential ana-
log outputs cannot be used in single-ended mode
because of the internally generated common-mode
level. Also, the Tx DAC analog outputs are designed to
drive a differential input stage with input impedance
≥ 70kΩ. If single-ended outputs are desired, use an
amplifier to provide differential-to-single-ended conver-
sion and select an amplifier with proper input common-
mode voltage range.
IDP
V
OUT
MAX19706
IDN
QDP
V
OUT
QDN
Figure 9. Balun Transformer-Coupled Differential-to-Single-
Ended Output Drive for Tx DAC
TDD Mode
The MAX19706 is optimized to operate in TDD applica-
tions. When FAST mode is selected, the MAX19706 can
switch between Tx and Rx modes through the T/R pin
in typically 0.5µs. The Rx ADC and Tx DAC operate
independently. The Rx ADC and Tx DAC digital bus are
shared forming a single 10-bit parallel bus. Using the 3-
wire serial interface or external T/R pin, select between
Rx mode to enable the Rx ADC or Tx mode to enable
the Tx DAC. When operating in Rx mode, the Tx DAC
bus is not enabled and in Tx mode the Rx ADC bus is
tri-stated, eliminating any unwanted spurious emissions
and preventing bus contention. In TDD mode, the
REFP
1kΩ
1kΩ
R
50Ω
ISO
V
IN
0.1µF
IAP
C
22pF
IN
100Ω
100Ω
COM
IAN
REFN
0.1µF
R
ISO
50Ω
MAX19706 uses 49.5mW power at f
= 22MHz.
CLK
C
IN
22pF
TDD Application
Figure 12 illustrates a typical TDD application circuit.
The MAX19706 interfaces directly with the radio front-
ends to provide a complete “RF-to-Bits” solution for
TDD applications. The MAX19706 provides several sys-
tem benefits to digital baseband developers.
REFP
MAX19706
R
50Ω
1kΩ
ISO
V
IN
0.1µF
QAP
•
•
•
•
•
•
•
Fast Time-to-Market
C
22pF
IN
100Ω
100Ω
1kΩ
High-Performance, Low-Power Analog Functions
Low Risk, Proven Analog Front-End Solution
No Mixed-Signal Test Times
No NRE Charges
REFN
0.1µF
R
50Ω
ISO
QAN
No IP Royalty Charges
C
22pF
IN
Enables Digital Baseband to Scale with 65nm to
90nm CMOS
Figure 10. Single-Ended Drive for Rx ADC
30 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
R4
R5
600Ω
600Ω
R
22Ω
ISO
R1
600Ω
IAN
C
IN
5pF
R2
600Ω
MAX19706
R6
R7
600Ω
600Ω
COM
R3
600Ω
R8
600Ω
R9
600Ω
R
ISO
22Ω
IAP
C
IN
5pF
R10
R11
600Ω
600Ω
Figure 11. Rx ADC DC-Coupled Differential Drive
10-BIT ADC
Rx-I
802.11X
Rx
ENCODE
T/R
Rx-Q
HALF-
DUPLEX
BUS
D9
D0
ZIF
10-BIT DAC
Tx-I
TRANSCEIVER
CLK
Tx
SOURCE
DIGITAL
BASEBAND
ASIC
Tx-Q
AGC
SCLK
DIN
12-BIT DAC
DAC3
SYSTEM
CONTROL
CLK DIST
SPI REG
CS
SHDN
DAC2
DAC1
0V
TCXO
REFIN
REFP
REFN
REF
1.024V
BUFFER
MAX19706
V
DD
DD
COM
BATTERY VOLTAGE MONITOR
TEMPERATURE MEASURE
ADC
10-BIT, 333ksps
DOUT
4:1 MUX
Figure 12. Typical Application Circuit for TDD Radio
______________________________________________________________________________________ 31
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
input lines to each respective converter to minimize
channel-to-channel crosstalk. Keep all signal lines
short and free of 90ꢀ turns.
Grounding, Bypassing, and
Board Layout
The MAX19706 requires high-speed board layout design
techniques. Refer to the MAX19707 EV kit data sheet for
a board layout reference. Place all bypass capacitors as
close to the device as possible, preferably on the same
side of the board as the device, using surface-mount
Dynamic Parameter Definitions
ADC and DAC Static Parameter Definitions
Integral Nonlinearity (INL)
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. This straight
line can be either a best-straight-line fit or a line drawn
between the end points of the transfer function, once
offset and gain errors have been nullified. The static lin-
earity parameters for the device are measured using
the best-straight-line fit (DAC Figure 13a).
devices for minimum inductance. Bypass V
to GND
DD
with a 0.1µF ceramic capacitor in parallel with a 2.2µF
capacitor. Bypass OV to OGND with a 0.1µF ceramic
DD
capacitor in parallel with a 2.2µF capacitor. Bypass
REFP, REFN, and COM each to GND with a 0.33µF
ceramic capacitor. Bypass REFIN to GND with a 0.1µF
capacitor.
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between an
actual step width and the ideal value of 1 LSB. A DNL
error specification of less than 1 LSB guarantees no
missing codes (ADC) and a monotonic transfer function
(ADC and DAC) (DAC Figure 13b).
Multilayer boards with separated ground and power
planes yield the highest level of signal integrity. Use a
split ground plane arranged to match the physical loca-
tion of the analog ground (GND) and the digital output-
driver ground (OGND) on the device package.
Connect the MAX19706 exposed backside paddle to
GND plane. Join the two ground planes at a single
point so the noisy digital ground currents do not inter-
fere with the analog ground plane. The ideal location
for this connection can be determined experimentally
at a point along the gap between the two ground
planes. Make this connection with a low-value, surface-
mount resistor (1Ω to 5Ω), a ferrite bead, or a direct
short. Alternatively, all ground pins could share the
same ground plane, if the ground plane is sufficiently
isolated from any noisy digital system’s ground plane
(e.g., downstream output buffer or DSP ground plane).
ADC Offset Error
Ideally, the midscale transition occurs at 0.5 LSB above
midscale. The offset error is the amount of deviation
between the measured transition point and the ideal
transition point.
DAC Offset Error
Offset error (Figure 13a) is the difference between the
ideal and actual offset point. The offset point is the out-
put value when the digital input is midscale. This error
affects all codes by the same amount and usually can
be compensated by trimming.
Route high-speed digital signal traces away from sensi-
tive analog traces. Make sure to isolate the analog
7
6
6
1 LSB
5
4
5
DIFFERENTIAL LINEARITY
ERROR (-0.25 LSB)
4
AT STEP
011 (0.5 LSB)
3
2
3
2
1
0
1 LSB
DIFFERENTIAL
LINEARITY ERROR (+0.25 LSB)
AT STEP
1
0
001 (0.25 LSB)
000
001
010
011
100
101
000 001 010 011 100 101 110 111
DIGITAL INPUT CODE
DIGITAL INPUT CODE
Figure 13b. Differential Nonlinearity
Figure 13a. Integral Nonlinearity
32 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
ADC Gain Error
Ideally, the ADC full-scale transition occurs at 1.5 LSB
below full scale. The gain error is the amount of devia-
tion between the measured transition point and the
ideal transition point with the offset error removed.
Signal-to-Noise and Distortion (SINAD)
SINAD is computed by taking the ratio of the RMS sig-
nal to the RMS noise. RMS noise includes all spectral
components to the Nyquist frequency excluding the
fundamental and the DC offset.
ADC Dynamic Parameter Definitions
Effective Number of Bits (ENOB)
ENOB specifies the dynamic performance of an ADC at a
specific input frequency and sampling rate. An ideal
ADC’s error consists of quantization noise only. ENOB for
a full-scale sinusoidal input waveform is computed from:
Aperture Jitter
Figure 14 shows the aperture jitter (t ), which is the
AJ
sample-to-sample variation in the aperture delay.
Aperture Delay
Aperture delay (t ) is the time defined between the
AD
ENOB = (SINAD - 1.76) / 6.02
rising edge of the sampling clock and the instant when
an actual sample is taken (Figure 14).
Total Harmonic Distortion (THD)
THD is typically the ratio of the RMS sum of the first five
harmonics of the input signal to the fundamental itself.
This is expressed as:
Signal-to-Noise Ratio (SNR)
For a waveform perfectly reconstructed from digital
samples, the theoretical maximum SNR is the ratio of
the full-scale analog input (RMS value) to the RMS
quantization error (residual error) and results directly
from the ADC’s resolution (N bits):
2
2
2
3
2
2
5
2
6
⎡
⎢
⎤
⎥
(V +V +V +V +V )
4
THD = 20 x log
V
⎢
⎣
⎥
⎦
1
SNR(max) = 6.02dB x N + 1.76dB (in dB)
where V is the fundamental amplitude and V –V are
1
2
6
the amplitudes of the 2nd- through 6th-order harmonics.
In reality, there are other noise sources besides quanti-
zation noise: thermal noise, reference noise, clock jitter,
etc. SNR is computed by taking the ratio of the RMS
signal to the RMS noise. RMS noise includes all spec-
tral components to the Nyquist frequency excluding the
fundamental, the first five harmonics, and the DC offset.
Third Harmonic Distortion (HD3)
HD3 is defined as the ratio of the RMS value of the third
harmonic component to the fundamental input signal.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio expressed in decibels of the RMS
amplitude of the fundamental (maximum signal compo-
nent) to the RMS value of the next-largest spurious
component, excluding DC offset.
CLK
Intermodulation Distortion (IMD)
IMD is the total power of the intermodulation products
relative to the total input power when two tones, f and
1
ANALOG
INPUT
f , are present at the inputs. The intermodulation prod-
2
ucts are (f
f ), (2 ✕ f ), (2 ✕ f ), (2 ✕ f
f ), (2 ✕ f
2 2
1
2
1
2
1
t
AD
f ). The individual input tone levels are at -7dBFS.
1
t
AJ
SAMPLED
DATA (T/H)
3rd-Order Intermodulation (IM3)
IM3 is the power of the worst 3rd-order intermodulation
product relative to the input power of either input tone
when two tones, f and f , are present at the inputs. The
1
2
HOLD
TRACK
TRACK
T/H
3rd-order intermodulation products are (2 x f
f ), (2 ✕
2
1
f
f ). The individual input tone levels are at -7dBFS.
2
1
Figure 14. T/H Aperture Timing
______________________________________________________________________________________ 33
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Power-Supply Rejection
Power-supply rejection is defined as the shift in offset
and gain error when the power supply is changed 5%.
DAC Dynamic Parameter Definitions
Total Harmonic Distortion
THD is the ratio of the RMS sum of the output harmonics
up to the Nyquist frequency divided by the fundamental:
Small-Signal Bandwidth
A small -20dBFS analog input signal is applied to an
ADC in so that the signal’s slew rate does not limit the
ADC’s performance. The input frequency is then swept
up to the point where the amplitude of the digitized
conversion result has decreased by 3dB. Note that the
T/H performance is usually the limiting factor for the
small-signal input bandwidth.
(V2 +V2 +... +V2)
⎡
⎢
⎤
⎥
2
3
n
THD = 20 x log
⎢
V
1
⎥
⎦
⎣
where V is the fundamental amplitude and V through
1
2
V are the amplitudes of the 2nd through nth harmonic
n
up to the Nyquist frequency.
Full-Power Bandwidth
A large -0.5dBFS analog input signal is applied to an
ADC, and the input frequency is swept up to the point
where the amplitude of the digitized conversion result
has decreased by 3dB. This point is defined as the full-
power bandwidth frequency.
Spurious-Free Dynamic Range
Spurious-free dynamic range (SFDR) is the ratio of RMS
amplitude of the fundamental (maximum signal compo-
nent) to the RMS value of the next-largest distortion
component up to the Nyquist frequency excluding DC.
Selector Guide
SAMPLING RATE
PART
DESCRIPTION
(Msps)
Dual 10-Bit Rx ADC, Dual 10-Bit Tx DAC, Integrated TD-SCDMA
Filters, Three 12-Bit Auxiliary DACs
MAX19700
7.5
Dual 10-Bit Rx ADC, Dual 10-Bit Tx DAC, Integrated TD-SCDMA
Filters, Three 12-Bit Auxiliary DACs, 10-Bit Auxiliary ADC with 4:1
Input Mux
MAX19708
11
Dual 10-Bit Rx ADC, Dual 10-Bit Tx DAC, Three 12-Bit Auxiliary
DACs, 10-Bit Auxiliary ADC with 4:1 Input Mux
MAX19705/MAX19706/MAX19707
7.5/22/45
34 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Functional Diagram
V
DD
= +2.7V TO +3.3V
OV = +1.8V TO +3.3V
DD
IAP
IAN
10-BIT
ADC
MAX19706
SHDN
T/R
QAP
QAN
10-BIT
ADC
D0–D9
HALF-
DUPLEX
BUS
IDP
IDN
10-BIT
DAC
QDP
QDN
10-BIT
DAC
SYSTEM
CLOCK
CLK
PROGRAMMABLE
OFFSET/CM
SERIAL
INTERFACE
AND SYSTEM
CONTROL
DIN
SCLK
CS
12-BIT
DAC
DAC1
DAC2
DAC3
12-BIT
DAC
REFIN
REFP
REFN
COM
1.024V
REFERENCE
BUFFER
12-BIT
DAC
V
DD
0V
DD
ADC1
ADC2
10-BIT
ADC
DOUT
4:1 MUX
GND
OGND
______________________________________________________________________________________ 35
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
E
DETAIL A
(NE-1) X
e
E/2
k
e
D/2
C
(ND-1) X
e
D2
D
L
D2/2
b
L
E2/2
C
L
k
DETAIL B
E2
e
C
C
L
L
L
L1
L
L
e
e
A
A1
A2
PACKAGE OUTLINE
32, 44, 48, 56L THIN QFN, 7x7x0.8mm
1
21-0144
E
2
36 ______________________________________________________________________________________
10-Bit, 22Msps, Ultra-Low-Power
Analog Front-End
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE
32, 44, 48, 56L THIN QFN, 7x7x0.8mm
2
21-0144
E
2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 37
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
Quijano
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