AD9629BCPZ-80 [ADI]

12-Bit, 20 MSPS/40 MSPS/65 MSPS/80 MSPS, 1.8 V Analog-to-Digital Converter; 12位, 20 MSPS / 40 MSPS / 65 MSPS / 80 MSPS , 1.8 V模拟数字转换器
AD9629BCPZ-80
型号: AD9629BCPZ-80
厂家: ADI    ADI
描述:

12-Bit, 20 MSPS/40 MSPS/65 MSPS/80 MSPS, 1.8 V Analog-to-Digital Converter
12位, 20 MSPS / 40 MSPS / 65 MSPS / 80 MSPS , 1.8 V模拟数字转换器

转换器
文件: 总32页 (文件大小:984K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
12-Bit, 20 MSPS/40 MSPS/65 MSPS/80 MSPS,  
1.8 V Analog-to-Digital Converter  
AD9629  
FEATURES  
FUNCTIONAL BLOCK DIAGRAM  
AVDD  
GND  
SDIO SCLK CSB  
DRVDD  
1.8 V analog supply operation  
1.8 V to 3.3 V output supply  
SNR  
RBIAS  
VCM  
SPI  
71.3 dBFS at 9.7 MHz input  
OR  
PROGRAMMING DATA  
69.0 dBFS at 200 MHz input  
SFDR  
95 dBc at 9.7 MHz input  
83 dBc at 200 MHz input  
Low power  
D11 (MSB)  
VIN+  
VIN–  
ADC  
CORE  
D0 (LSB)  
DCO  
VREF  
SENSE  
45 mW at 20 MSPS  
85 mW at 80 MSPS  
AD9629  
REF  
SELECT  
Differential input with 700 MHz bandwidth  
On-chip voltage reference and sample-and-hold circuit  
2 V p-p differential analog input  
DNL = 0.16 LSB  
MODE  
DIVIDE BY  
1, 2, 4  
CONTROLS  
CLK+ CLK–  
PDWN DFS MODE  
Serial port control options  
Figure 1.  
Offset binary, gray code, or twos complement data format  
Integer 1, 2, or 4 input clock divider  
Built-in selectable digital test pattern generation  
Energy-saving power-down modes  
Data clock out with programmable clock and data alignment  
PRODUCT HIGHLIGHTS  
1. The AD9629 operates from a single 1.8 V analog power  
supply and features a separate digital output driver supply  
to accommodate 1.8 V to 3.3 V logic families.  
2. The patented sample-and-hold circuit maintains excellent  
performance for input frequencies up to 200 MHz and is  
designed for low cost, low power, and ease of use.  
3. A standard serial port interface (SPI) supports various  
product features and functions, such as data output format-  
ting, internal clock divider, power-down, DCO and data  
output (D11 to D0) timing and offset adjustments, and  
voltage reference modes.  
4. The AD9629 is packaged in a 32-lead RoHS compliant LFCSP  
that is pin compatible with the AD9609 10-bit ADC and  
the AD9649 14-bit ADC, enabling a simple migration path  
between 10-bit and 14-bit converters sampling from 20 MSPS  
to 80 MSPS.  
APPLICATIONS  
Communications  
Diversity radio systems  
Multimode digital receivers  
GSM, EDGE, W-CDMA, LTE, CDMA2000, WiMAX, TD-SCDMA  
Smart antenna systems  
Battery-powered instruments  
Hand held scope meters  
Portable medical imaging  
Ultrasound  
Radar/LIDAR  
PET/SPECT imaging  
Rev. 0  
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 registeredtrademarks arethe 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  
©2009 Analog Devices, Inc. All rights reserved.  
 
 
 
AD9629  
TABLE OF CONTENTS  
Features .............................................................................................. 1  
Voltage Reference ....................................................................... 19  
Clock Input Considerations...................................................... 20  
Power Dissipation and Standby Mode .................................... 21  
Digital Outputs ........................................................................... 22  
Timing ......................................................................................... 22  
Built-In Self-Test (BIST) and Output Test .................................. 23  
Built-In Self-Test (BIST)............................................................ 23  
Output Test Modes..................................................................... 23  
Serial Port Interface (SPI).............................................................. 24  
Configuration Using the SPI..................................................... 24  
Hardware Interface..................................................................... 25  
Configuration Without the SPI ................................................ 25  
SPI Accessible Features.............................................................. 25  
Memory Map .................................................................................. 26  
Reading the Memory Map Register Table............................... 26  
Open Locations .......................................................................... 26  
Default Values............................................................................. 26  
Memory Map Register Table..................................................... 27  
Memory Map Register Descriptions........................................ 29  
Applications Information.............................................................. 30  
Design Guidelines ...................................................................... 30  
Outline Dimensions....................................................................... 31  
Ordering Guide .......................................................................... 31  
Applications....................................................................................... 1  
Functional Block Diagram .............................................................. 1  
Product Highlights ........................................................................... 1  
Revision History ............................................................................... 2  
General Description......................................................................... 3  
Specifications..................................................................................... 4  
DC Specifications ......................................................................... 4  
AC Specifications.......................................................................... 5  
Digital Specifications ................................................................... 6  
Switching Specifications .............................................................. 7  
Timing Specifications .................................................................. 8  
Absolute Maximum Ratings............................................................ 9  
Thermal Characteristics .............................................................. 9  
ESD Caution.................................................................................. 9  
Pin Configuration and Function Descriptions........................... 10  
Typical Performance Characteristics ........................................... 11  
AD9629-80 .................................................................................. 11  
AD9629-65 .................................................................................. 13  
AD9629-40 .................................................................................. 14  
AD9629-20 .................................................................................. 15  
Equivalent Circuits......................................................................... 16  
Theory of Operation ...................................................................... 17  
Analog Input Considerations.................................................... 17  
REVISION HISTORY  
10/09—Revision 0: Initial Version  
Rev. 0 | Page 2 of 32  
 
AD9629  
GENERAL DESCRIPTION  
deterministic and pseudorandom patterns, along with custom  
user-defined test patterns entered via the serial port interface (SPI).  
The AD9629 is a monolithic, single channel 1.8 V supply, 12-bit,  
20 MSPS/40 MSPS/65 MSPS/80 MSPS analog-to-digital conver-  
ter (ADC). It features a high performance sample-and-hold  
circuit and on-chip voltage reference.  
A differential clock input with optional 1, 2, or 4 divide ratios  
controls all internal conversion cycles.  
The product uses multistage differential pipeline architecture  
with output error correction logic to provide 12-bit accuracy at  
80 MSPS data rates and to guarantee no missing codes over the  
full operating temperature range.  
The digital output data is presented in offset binary, gray code,  
or twos complement format. A data output clock (DCO) is  
provided to ensure proper latch timing with receiving logic. Both  
1.8 V and 3.3 V CMOS levels are supported.  
The ADC contains several features designed to maximize  
flexibility and minimize system cost, such as programmable  
clock and data alignment and programmable digital test pattern  
generation. The available digital test patterns include built-in  
The AD9629 is available in a 32-lead RoHS compliant LFCSP  
and is specified over the industrial temperature range (−40°C  
to +85°C).  
Rev. 0 | Page 3 of 32  
 
AD9629  
SPECIFICATIONS  
DC SPECIFICATIONS  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
Table 1.  
AD9629-20/AD9629-40  
Temp Min Typ Max  
AD9629-65  
AD9629-80  
Parameter  
Min  
Typ  
Max  
Min  
Typ  
Max  
Unit  
RESOLUTION  
Full  
12  
12  
12  
Bits  
ACCURACY  
No Missing Codes  
Offset Error  
Full  
Full  
Full  
Full  
25°C  
Full  
25°C  
Guaranteed  
Guaranteed  
Guaranteed  
−0.40 +0.05  
−1.5  
+0.50  
−0.40 +0.05 +0.50 −0.40 +0.05 +0.50 % FSR  
−1.5 −1.5 % FSR  
0.30 LSB  
Gain Error1  
Differential Nonlinearity (DNL)2  
0.25  
0.25  
0.30  
0.11  
0.11  
2
0.11  
0.1ꢀ  
LSB  
0.35 LSB  
LSB  
Integral Nonlinearity (INL)2  
0.40  
0.13  
2
0.1ꢀ  
2
TEMPERATURE DRIFT  
Offset Error  
Full  
ppm/°C  
INTERNAL VOLTAGE REFERENCE  
Output Voltage (1 V Mode)  
Load Regulation Error at 1.0 mA  
INPUT-REFERRED NOISE  
VREF = 1.0 V  
Full  
Full  
0.984 0.99ꢀ  
2
1.008  
0.984 0.99ꢀ 1.008 0.984 0.99ꢀ 1.008  
V
mV  
2
2
25°C  
0.25  
0.25  
0.25  
LSB rms  
ANALOG INPUT  
Input Span, VREF = 1.0 V  
Input Capacitance3  
Input Common-Mode Voltage  
Input Common-Mode Range  
REFERENCE INPUT RESISTANCE  
POWER SUPPLIES  
Supply Voltage  
AVDD  
DRVDD  
Full  
Full  
Full  
Full  
Full  
2
0.9  
2
0.9  
2
0.9  
V p-p  
pF  
V
0.5  
1.3  
0.5  
1.3  
0.5  
1.3  
V
7.5  
7.5  
1.8  
7.5  
1.8  
kΩ  
Full  
Full  
1.7  
1.7  
1.8  
1.9  
3.ꢀ  
1.7  
1.7  
1.9  
3.ꢀ  
1.7  
1.7  
1.9  
3.ꢀ  
V
V
Supply Current  
IAVDD2  
Full  
Full  
Full  
24.9/31.1 2ꢀ.7/33.2  
1.5/2.5  
2.7/4.7  
41.2  
4.2  
7.5  
4ꢀ.0  
4ꢀ.8  
5.0  
9.0  
50.0  
mA  
mA  
mA  
IDRVDD2 (1.8 V)  
IDRVDD2 (3.3 V)  
POWER CONSUMPTION  
DC Input  
Sine Wave Input2 (DRVDD = 1.8 V)  
Sine Wave Input2 (DRVDD = 3.3 V)  
Standby Power4  
Full  
Full  
Full  
Full  
Full  
45.0/5ꢀ.7  
47.5/ꢀ0.5 50.7/ꢀ5.0  
53.7/71.7  
34  
0.5  
75  
85.2  
93  
114  
34  
mW  
mW  
mW  
mW  
mW  
81.7  
98.9  
34  
8ꢀ.0  
100  
Power-Down Power  
0.5  
0.5  
1 Measured with 1.0 V external reference.  
2 Measured with a 10 MHz input frequency at rated sample rate, full-scale sine wave, with approximately 5 pF loading on each output bit.  
3 Input capacitance refers to the effective capacitance between one differential input pin and AGND.  
4 Standby power is measured with a dc input and the clock active.  
Rev. 0 | Page 4 of 32  
 
 
AD9629  
AC SPECIFICATIONS  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
Table 2.  
AD9629-20/AD9629-40  
AD9629-65  
AD9629-80  
Parameter1  
Temp Min  
Typ  
Max  
Min Typ Max Min Typ  
Max Unit  
SIGNAL-TO-NOISE RATIO (SNR)  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
25°C  
25°C  
Full  
25°C  
Full  
25°C  
71.4  
71.2  
71.3  
71.2  
71.3  
71.2  
dBFS  
dBFS  
dBFS  
dBFS  
dBFS  
dBFS  
70.5/70.7  
70.ꢀ  
70.5  
fIN = 70 MHz  
70.5/71.0  
71.0  
ꢀ9.0  
70.9  
ꢀ9.0  
70.3  
70.2  
fIN = 200 MHz  
SIGNAL-TO-NOISE-AND-DISTORTION (SINAD)  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
25°C  
25°C  
Full  
25°C  
Full  
71.4  
71.2  
71.3  
71.2  
71.2  
71.1  
dBFS  
dBFS  
dBFS  
dBFS  
dBFS  
dBFS  
70.5/70.ꢀ  
fIN = 70 MHz  
70.4/70.9  
ꢀ8  
70.9  
ꢀ8  
70.8  
ꢀ8  
fIN = 200 MHz  
25°C  
EFFECTIVE NUMBER OF BITS (ENOB)  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
fIN = 70 MHz  
fIN = 200 MHz  
25°C  
25°C  
25°C  
25°C  
11.4/11.ꢀ  
11.4/11.5  
11.4/11.5  
11.0  
11.ꢀ  
11.5  
11.5  
11.0  
11.5  
11.5  
11.5  
11.0  
Bits  
Bits  
Bits  
Bits  
WORST SECOND OR THIRD HARMONIC  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
25°C  
25°C  
Full  
25°C  
Full  
−97  
−95  
−97  
−95  
−95  
−94  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
−83  
−83  
fIN = 70 MHz  
−9ꢀ/−94  
−83  
−95  
−83  
−95  
−83  
−81  
fIN = 200 MHz  
25°C  
SPURIOUS-FREE DYNAMIC RANGE (SFDR)  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
25°C  
25°C  
Full  
25°C  
Full  
97  
9ꢀ/95  
97  
95  
95  
93  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
83  
83  
fIN = 70 MHz  
9ꢀ/94  
83  
95  
83  
95  
83  
81  
fIN = 200 MHz  
25°C  
WORST OTHER (HARMONIC OR SPUR)  
fIN = 9.7 MHz  
fIN = 30.5 MHz  
25°C  
25°C  
Full  
25°C  
Full  
−100  
−100  
−100  
−100  
−100  
−100  
dBc  
dBc  
dBc  
dBc  
dBc  
dBc  
−92/−91  
−93  
fIN = 70 MHz  
−97/−100  
−92  
−100  
−92  
−100  
−92  
−89  
fIN = 200 MHz  
25°C  
TWO-TONE SFDR  
fIN = 30.5 MHz (−7 dBFS), 32.5 MHz (−7 dBFS)  
ANALOG INPUT BANDWIDTH  
25°C  
25°C  
90  
90  
90  
dBc  
700  
700  
700  
MHz  
1 See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for a complete set of definitions.  
Rev. 0 | Page 5 of 32  
 
AD9629  
DIGITAL SPECIFICATIONS  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
Table 3.  
AD9629-20/AD9629-40/AD9629-65/AD9629-80  
Parameter  
Temp  
Min  
Typ  
Max  
Unit  
DIFFERENTIAL CLOCK INPUTS (CLK+, CLK−)  
Logic Compliance  
Internal Common-Mode Bias  
Differential Input Voltage  
Input Voltage Range  
High Level Input Current  
Low Level Input Current  
Input Resistance  
CMOS/LVDS/LVPECL  
0.9  
Full  
Full  
Full  
Full  
Full  
Full  
Full  
V
0.2  
GND − 0.3  
−10  
−10  
8
3.ꢀ  
AVDD + 0.2  
+10  
+10  
12  
V p-p  
V
μA  
μA  
kΩ  
pF  
10  
4
Input Capacitance  
LOGIC INPUTS (SCLK/DFS, MODE, SDIO/PDWN)1  
High Level Input Voltage  
Low Level Input Voltage  
High Level Input Current  
Low Level Input Current  
Input Resistance  
Full  
Full  
Full  
Full  
Full  
Full  
1.2  
0
−50  
−10  
DRVDD + 0.3  
0.8  
−75  
+10  
V
V
μA  
μA  
kΩ  
pF  
30  
2
Input Capacitance  
LOGIC INPUTS (CSB)2  
High Level Input Voltage  
Low Level Input Voltage  
High Level Input Current  
Low Level Input Current  
Input Resistance  
Full  
Full  
Full  
Full  
Full  
Full  
1.2  
0
−10  
40  
DRVDD + 0.3  
0.8  
+10  
135  
V
V
μA  
μA  
kΩ  
pF  
2ꢀ  
2
Input Capacitance  
DIGITAL OUTPUTS  
DRVDD = 3.3 V  
High Level Output Voltage, IOH = 50 μA  
High Level Output Voltage, IOH = 0.5 mA  
Low Level Output Voltage, IOL = 1.ꢀ mA  
Low Level Output Voltage, IOL = 50 μA  
DRVDD = 1.8 V  
Full  
Full  
Full  
Full  
3.29  
3.25  
V
V
V
V
0.2  
0.05  
High Level Output Voltage, IOH = 50 μA  
High Level Output Voltage, IOH = 0.5 mA  
Low Level Output Voltage, IOL = 1.ꢀ mA  
Low Level Output Voltage, IOL = 50 μA  
Full  
Full  
Full  
Full  
1.79  
1.75  
V
V
V
V
0.2  
0.05  
1 Internal 30 kΩ pull-down.  
2 Internal 30 kΩ pull-up.  
Rev. 0 | Page ꢀ of 32  
 
AD9629  
SWITCHING SPECIFICATIONS  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
Table 4.  
AD9629-20/AD9629-40  
AD9629-65  
AD9629-80  
Max Min Typ Max Unit  
Parameter  
Temp Min  
Typ  
Max  
Min  
Typ  
CLOCK INPUT PARAMETERS  
Input Clock Rate1  
Conversion Rate2  
CLK Period, Divide-by-1 Mode (tCLK  
CLK Pulse Width High (tCH)  
Aperture Delay (tA)  
Aperture Uncertainty (Jitter, tJ)  
DATA OUTPUT PARAMETERS  
Data Propagation Delay (tPD)  
Full  
Full  
Full  
80/1ꢀ0  
20/40  
2ꢀ0  
ꢀ5  
320  
80  
MHz  
MSPS  
ns  
ns  
ns  
3
3
3
12.5  
50/25  
)
15.38  
25.0/12.5  
1.0  
0.1  
7.ꢀ9  
1.0  
0.1  
ꢀ.25  
1.0  
0.1  
Full  
Full  
ps rms  
Full  
Full  
Full  
Full  
Full  
Full  
Full  
3
3
0.1  
8
350  
ꢀ00/400  
2
3
3
3
3
ns  
ns  
ns  
Cycles  
μs  
DCO Propagation Delay (tDCO  
)
DCO to Data Skew (tSKEW  
)
0.1  
8
350  
300  
2
0.1  
8
350  
2ꢀ0  
2
Pipeline Delay (Latency)  
Wake-Up Time3  
Standby  
ns  
OUT-OF-RANGE RECOVERY TIME  
Cycles  
1 Input clock rate is the clock rate before the internal CLK divider.  
2 Conversion rate is the clock rate after the CLK divider.  
3 Wake-up time is dependent on the value of the decoupling capacitors.  
N – 1  
N + 4  
tA  
N + 5  
N
N + 3  
VIN  
N + 1  
N + 2  
tCH  
tCLK  
CLK+  
CLK–  
tDCO  
DCO  
tSKEW  
N – 8  
DATA  
N – 7  
N – 6  
N – 5  
N – 4  
tPD  
Figure 2. CMOS Output Data Timing  
Rev. 0 | Page 7 of 32  
 
 
AD9629  
TIMING SPECIFICATIONS  
Table 5.  
Parameter  
Conditions  
Min  
Typ  
Max  
Unit  
SPI TIMING REQUIREMENTS  
tDS  
tDH  
tCLK  
tS  
tH  
tHIGH  
tLOW  
tEN_SDIO  
Setup time between the data and the rising edge of SCLK  
Hold time between the data and the rising edge of SCLK  
Period of the SCLK  
Setup time between CSB and SCLK  
Hold time between CSB and SCLK  
SCLK pulse width high  
SCLK pulse width low  
Time required for the SDIO pin to switch from an input to an  
output relative to the SCLK falling edge  
2
2
40  
2
2
10  
10  
10  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
tDIS_SDIO  
Time required for the SDIO pin to switch from an output to an  
input relative to the SCLK rising edge  
10  
ns  
Rev. 0 | Page 8 of 32  
 
 
AD9629  
ABSOLUTE MAXIMUM RATINGS  
THERMAL CHARACTERISTICS  
Table 6.  
Parameter  
Rating  
The exposed paddle is the only ground connection for the chip.  
The exposed paddle must be soldered to the AGND plane of the  
users circuit board. Soldering the exposed paddle to the users  
board also increases the reliability of the solder joints and  
maximizes the thermal capability of the package.  
AVDD to AGND  
DRVDD to AGND  
VIN+, VIN− to AGND  
CLK+, CLK− to AGND  
VREF to AGND  
SENSE to AGND  
VCM to AGND  
RBIAS to AGND  
CSB to AGND  
SCLK/DFS to AGND  
SDIO/PDWN to AGND  
MODE/OR to AGND  
D0 through D11 to AGND  
DCO to AGND  
Operating Temperature Range (Ambient)  
Maximum Junction Temperature Under Bias  
Storage Temperature Range (Ambient)  
−0.3 V to +2.0 V  
−0.3 V to +3.9 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to AVDD + 0.2 V  
−0.3 V to DRVDD + 0.3 V  
−0.3 V to DRVDD + 0.3 V  
−0.3 V to DRVDD + 0.3 V  
−0.3 V to DRVDD + 0.3 V  
−0.3 V to DRVDD + 0.3 V  
−0.3 V to DRVDD + 0.3 V  
−40°C to +85°C  
Table 7. Thermal Resistance  
Airflow  
Package Velocity  
1, 2  
1, 3  
1, 4  
1, 2  
Type  
(m/sec)  
θJA  
θJC  
θJB  
20.7  
ΨJT  
0.3  
0.5  
0.8  
Unit  
°C/W  
°C/W  
°C/W  
32-Lead  
LFCSP  
5 mm ×  
5 mm  
0
1.0  
2.5  
37.1  
32.4  
29.1  
3.1  
1 Per JEDEC 51-7, plus JEDEC 51-5 2S2P test board.  
2 Per JEDEC JESD51-2 (still air) or JEDEC JESD51-ꢀ (moving air).  
3 Per MIL-Std 883, Method 1012.1.  
4 Per JEDEC JESD51-8 (still air).  
150°C  
−ꢀ5°C to +150°C  
Typical θJA is specified for a 4-layer PCB with a solid ground  
plane. As shown in Table 7, airflow improves heat dissipation,  
which reduces θJA. In addition, metal in direct contact with the  
package leads from metal traces, through holes, ground, and  
power planes, reduces the θJA.  
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  
section of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
ESD CAUTION  
Rev. 0 | Page 9 of 32  
 
 
 
 
AD9629  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
CLK+  
CLK–  
AVDD  
1
2
3
4
5
6
7
8
24 AVDD  
23 MODE/OR  
22 DCO  
21 D11 (MSB)  
20 D10  
19 D9  
18 D8  
17 D7  
PIN 1  
INDICATOR  
CSB  
AD9629  
TOP VIEW  
SCLK/DFS  
SDIO/PDWN  
NC  
(Not to Scale)  
NC  
NOTES  
1. NC = NO CONNECT.  
2. THE EXPOSED PADDLE MUST BE SOLDERED TO  
THE PCB GROUND TO ENSURE PROPER HEAT DISSIPATION,  
NOISE, AND MECHANICAL STRENGTH BENEFITS.  
Figure 3. Pin Configuration  
Table 8. Pin Function Description  
Pin No.  
Mnemonic  
Description  
0 (EPAD)  
GND  
Exposed Paddle. The exposed paddle is the only ground connection. It must be soldered to the analog  
ground of the customer’s PCB to ensure proper functionality and maximize heat dissipation, noise, and  
mechanical strength benefits.  
1, 2  
3, 24, 29, 32  
CLK+, CLK−  
AVDD  
Differential Encode Clock. PECL, LVDS, or 1.8 V CMOS inputs.  
1.8 V Supply Pin for ADC Core Domain.  
4
5
CSB  
SCLK/DFS  
SPI Chip Select. Active low enable. 30 kΩ internal pull-up.  
SPI Clock Input in SPI Mode (SCLK). 30 kΩ internal pull-down.  
Data Format Select in Non-SPI Mode (DFS). Static control of data output format. 30 kΩ internal pull-down.  
DFS high = twos complement output; DFS low = offset binary output.  
SDIO/PDWN  
SPI Data Input/Output (SDIO). Bidirectional SPI data I/O in SPI mode. 30 kΩ internal pull-down.  
Non-SPI Mode Power-Down (PDWN). Static control of power-down with 30 kΩ internal pull-down. See  
Table 14 for details.  
7, 8  
NC  
Do Not Connect.  
9 to 12, 14 to 21 D0 (LSB) to  
D11 (MSB)  
ADC Digital Outputs.  
13  
22  
23  
DRVDD  
DCO  
MODE/OR  
1.8 V to 3.3 V Supply Pin for Output Driver Domain.  
Data Clock Digital Output.  
Chip Mode Select Input or Out-of-Range (OR) Digital Output in SPI Mode.  
Default = out-of-range (OR) digital output (SPI Register 0x2A[0] = 1).  
Option = chip mode select input (SPI Register 0x2A[0] = 0).  
Chip power down (SPI Register 0x08[7:5] = 100b).  
Chip standby (SPI Register 0x08[7:5] = 101b).  
Normal operation, output disabled (SPI Register 0x08[7:5] = 110b).  
Normal operation, output enabled (SPI Register 0x08[7:5] = 111b).  
Out-of-Range (OR) digital output only in non-SPI mode.  
25  
2ꢀ  
27  
28  
VREF  
SENSE  
VCM  
RBIAS  
VIN−, VIN+  
1.0 V Voltage Reference Input/Output. See Table 10.  
Reference Mode Selection. See Table 10.  
Analog Output Voltage at Mid AVDD Supply. Sets common mode of the analog inputs.  
Sets Analog Current Bias. Connect to 10 kΩ (1% tolerance) resistor to ground.  
ADC Analog Inputs.  
30, 31  
Rev. 0 | Page 10 of 32  
 
AD9629  
TYPICAL PERFORMANCE CHARACTERISTICS  
AD9629-80  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
0
0
80MSPS  
–15  
–30  
80MSPS  
–15  
–30  
30.6MHz @ –1dBFS  
SNR = 70.1dB (71.1dBFS)  
SFDR = 94.4dBc  
9.7MHz @ –1dBFS  
SNR = 70.2dB (71.2dBFS)  
SFDR = 93.6dBc  
–45  
–45  
–60  
–60  
–75  
–75  
–90  
+
–90  
3
+
2
6
2
4
3
5
5
4
–105  
–120  
–135  
6
–105  
–120  
–135  
0
4
8
12  
16  
20  
24  
28  
32  
36  
40  
0
4
8
12  
16  
20  
24  
28  
32  
36  
40  
FREQUENCY (MHz)  
FREQUENCY (MHz)  
Figure 7. AD9629-80 Single-Tone FFT with fIN = 30.6 MHz  
Figure 4. AD9629-80 Single-Tone FFT with fIN = 9.7 MHz  
0
–15  
0
80MSPS  
80MSPS  
–15  
–30  
69MHz @ –1dBFS  
SNR = 69.9dB (70.9dBFS)  
SFDR = 94.3dBc  
210.3MHz @ –1dBFS  
SNR = 67.9dB (68.9dBFS)  
SFDR = 83.2dBc  
–30  
–45  
–45  
–60  
–60  
–75  
–75  
2
3
–90  
+
–90  
+
6
4
2
6
3
5
5
4
–105  
–120  
–135  
–105  
–120  
–135  
0
4
8
12  
16  
20  
24  
28  
32  
36  
40  
0
4
8
12  
16  
20  
24  
28  
32  
36  
40  
FREQUENCY (MHz)  
FREQUENCY (MHz)  
Figure 5. AD9629-80 Single-Tone FFT with fIN = 69 MHz  
Figure 8. AD9629-80 Single-Tone FFT with fIN = 210.3 MHz  
0
–15  
0
80MSPS  
28.3 @ –7dBFS  
30.6 @ –7dBFS  
SFDR = 90dBc  
–30  
–20  
SFDR (dBc)  
IMD3 (dBc)  
–45  
–40  
–60  
–60  
–75  
–90  
F1 + F2  
F2 – F1 2F2 – F1  
2F2 – F1  
2F1 – F2  
2F1 + F2  
–80  
–105  
–120  
–135  
SFDR (dBFS)  
–100  
–120  
IMD3 (dBFS)  
–60  
0
4
8
12  
16  
20  
24  
28  
32  
36  
40  
FREQUENCY (MHz)  
–70  
–50  
–40  
–30  
–20  
–10  
INPUT AMPLITUDE (dBFS)  
Figure 6. AD9629-80 Two-Tone FFT with fIN1 = 28.3 MHz and fIN2 = 30.6 MHz  
Figure 9. Two-Tone SFDR/IMD3 vs. Input Amplitude (AIN) with fIN1 = 30.5 MHz  
and fIN2 = 32.5 MHz  
Rev. 0 | Page 11 of 32  
 
 
AD9629  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
0.3  
SFDR  
0.2  
SNR  
0.1  
0
–0.1  
–0.2  
–0.3  
0
500  
1000 1500 2000 2500 3000  
OUTPUT CODE  
3500 4000  
0
50  
100  
INPUT FREQUENCY (MHz)  
150  
200  
Figure 13. DNL Error with fIN = 9.7 MHz  
Figure 10. AD9629-80 SNR/SFDR vs. Input Frequency (AIN) with 2 V p-p Full Scale  
100  
0.4  
0.2  
0
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
SFDR  
SNRFS  
–0.2  
0.4  
0
500  
1000 1500 2000 2500 3000 3500 4000  
OUTPUT CODE  
10  
20  
30  
40  
50  
60  
70  
80  
SAMPLE RATE (MHz)  
Figure 11. AD9629-80 SNR/SFDR vs. Sample Rate with AIN = 9.7 MHz  
Figure 14. INL with fIN = 9.7 MHz  
100  
90  
SFDRFS  
80  
SNRFS  
70  
60  
SFDR  
50  
SNR  
40  
30  
20  
10  
0
–70  
–60  
–50  
–40  
–30  
–20  
–10  
0
INPUT AMPLITUDE (dBc)  
Figure 12. AD9629-80 SNR/SFDR vs. Input Amplitude (AIN) with fIN = 9.7 MHz  
Rev. 0 | Page 12 of 32  
AD9629  
AD9629-65  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
0
120  
100  
80  
60  
40  
20  
0
65MSPS  
–15  
9.7MHz @ –1dBFS  
SNR =70.3 (71.3dBFS)  
SFDR = 94.2dBc  
SFDRFS  
–30  
–45  
SNRFS  
SFDR  
–60  
–75  
–90  
+
2
3
5
6
4
SNR  
–105  
–120  
–135  
0
3
6
9
12  
15  
18  
21  
24  
27  
30  
33  
33  
33  
–70  
–60  
–50  
–40  
–30  
–20  
–10  
0
FREQUENCY (MHz)  
INPUT AMPLITUDE (dBc)  
Figure 15. AD9629-65 Single-Tone FFT with fIN = 9.7 MHz  
Figure 18. AD9629-65 SNR/SFDR vs. Input Amplitude (AIN) with fIN = 9.7 MHz  
0
100  
65MSPS  
90  
–15  
–30  
SFDR  
69MHz @ –1dBFS  
SNR = 69.9dB (70.9dBFS)  
SFDR = 92.0dBc  
80  
SNR  
70  
–45  
60  
50  
40  
30  
20  
10  
0
–60  
–75  
–90  
+
2
5
4
3
6
–105  
–120  
–135  
0
3
6
9
12  
15  
18  
21  
24  
27  
30  
0
50  
100  
150  
200  
FREQUENCY (MHz)  
INPUT FREQUENCY (MHz)  
Figure 16. AD9629-65 Single-Tone FFT with fIN = 69 MHz  
Figure 19. AD9629-65 SNR/SFDR vs. Input Frequency (AIN) with  
2 V p-p Full Scale  
0
65MSPS  
–15  
–30  
30.6MHz @ –1dBFS  
SNR = 70.2dB (71.2dBFS)  
SFDR = 94.1dBc  
–45  
–60  
–75  
–90  
+
3
2
5
6
4
–105  
–120  
–135  
0
3
6
9
12  
15  
18  
21  
24  
27  
30  
FREQUENCY (MHz)  
Figure 17. AD9629-65 Single-Tone FFT with fIN = 30.6 MHz  
Rev. 0 | Page 13 of 32  
 
AD9629  
AD9629-40  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
0
120  
100  
80  
60  
40  
20  
0
40MSPS  
–15  
9.7MHz @ –1dBFS  
SNR = 70.3dB (71.3dBFS)  
SFDR = 93.8dBc  
SFDRFS  
SNRFS  
–30  
–45  
–60  
–75  
SFDR  
SNR  
–90  
+
2
3
5
4
6
–105  
–120  
–135  
0
2
4
6
8
10  
12  
14  
16  
18  
20  
–70  
–60  
–50  
–40  
–30  
–20  
–10  
0
FREQUENCY (MHz)  
INPUT AMPLITUDE (dBc)  
Figure 20. AD9629-40 Single-Tone FFT with fIN = 9.7 MHz  
Figure 22. AD9629-40 SNR/SFDR vs. Input Amplitude (AIN) with fIN = 9.7 MHz  
0
40MSPS  
–15  
–30  
30.6MHz @ –1dBFS  
SNR = 70.2dB (71.2dBFS)  
SFDR = 95.4dBc  
–45  
–60  
–75  
–90  
+
5
3
6
2
4
–105  
–120  
–135  
0
2
4
6
8
10  
12  
14  
16  
18  
20  
FREQUENCY (MHz)  
Figure 21. AD9629-40 Single-Tone FFT with fIN = 30.6 MHz  
Rev. 0 | Page 14 of 32  
 
AD9629  
AD9629-20  
AVDD = 1.8 V; DRVDD = 1.8 V, maximum sample rate, 2 V p-p differential input, 1.0 V internal reference; AIN = −1.0 dBFS, 50% duty  
cycle clock, unless otherwise noted.  
0
120  
100  
80  
60  
40  
20  
0
20MSPS  
–15  
SFDRFS  
9.7MHz @ –1dBFS  
SNR = 70.3dB (71.3dBFS)  
SFDR = 94.1dBc  
–30  
–45  
SNRFS  
SFDR  
–60  
–75  
–90  
+
2
5
3
SNR  
4
6
–105  
–120  
–135  
0
0.95 1.90 2.85 3.80 4.75 5.70 6.65 7.60 8.55 9.50  
FREQUENCY (MHz)  
–70  
–60  
–50  
–40  
–30  
–20  
–10  
0
INPUT AMPLITUDE (dBc)  
Figure 23. AD9629-20 Single-Tone FFT with fIN = 9.7 MHz  
Figure 25. AD9629-20 SNR/SFDR vs. Input Amplitude (AIN) with fIN = 9.7 MHz  
0
20MSPS  
–15  
30.6MHz @ –1dBFS  
SNR = 70.2dB (71.2dBFS)  
SFDR = 94.6dBc  
–30  
–45  
–60  
–75  
–90  
+
5
4
2
3
6
–105  
–120  
–135  
0
0.95 1.90 2.85 3.80 4.75 5.70 6.65 7.60 8.55 9.50  
FREQUENCY (MHz)  
Figure 24. AD9629-20 Single-Tone FFT with fIN = 30.6 MHz  
Rev. 0 | Page 15 of 32  
 
AD9629  
EQUIVALENT CIRCUITS  
DRVDD  
AVDD  
VIN±  
Figure 26. Equivalent Analog Input Circuit  
Figure 30. Equivalent D0 to D11 and OR Digital Output Circuit  
DRVDD  
AVDD  
350  
SCLK/DFS, MODE,  
375  
SDIO/PDWN  
VREF  
30kΩ  
7.5kΩ  
Figure 27. Equivalent VREF Circuit  
Figure 31. Equivalent SCLK/DFS, MODE, and SDIO/PDWN Input Circuit  
AVDD  
DRVDD  
AVDD  
30k  
375  
350Ω  
SENSE  
CSB  
Figure 28. Equivalent SENSE Circuit  
Figure 32. Equivalent CSB Input Circuit  
5  
CLK+  
15kΩ  
0.9V  
AVDD  
15kΩ  
5Ω  
CLK–  
375  
RBIAS  
AND VCM  
Figure 29. Equivalent Clock Input Circuit  
Figure 33. Equivalent RBIAS and VCM Circuit  
Rev. 0 | Page 1ꢀ of 32  
 
 
AD9629  
THEORY OF OPERATION  
high IF frequencies. Either a shunt capacitor or two single-ended  
capacitors can be placed on the inputs to provide a matching  
passive network. This ultimately creates a low-pass filter at the  
input to limit unwanted broadband noise. See the AN-742  
Application Note, the AN-827 Application Note, and the Analog  
Dialogue article “Transformer-Coupled Front-End for Wideband  
A/D Converters” (Volume 39, April 2005) for more information.  
In general, the precise values depend on the application.  
The AD9629 architecture consists of a multistage, pipelined ADC.  
Each stage provides sufficient overlap to correct for flash errors in  
the preceding stage. The quantized outputs from each stage are  
combined into a final 12-bit result in the digital correction logic.  
The pipelined architecture permits the first stage to operate with a  
new input sample while the remaining stages operate with pre-  
ceding samples. Sampling occurs on the rising edge of the clock.  
Each stage of the pipeline, excluding the last, consists of a low  
resolution flash ADC connected to a switched-capacitor DAC  
and an interstage residue amplifier (for example, a multiplying  
digital-to-analog converter (MDAC)). The residue amplifier  
magnifies the difference between the reconstructed DAC output  
and the flash input for the next stage in the pipeline. One bit of  
redundancy is used in each stage to facilitate digital correction  
of flash errors. The last stage consists of a flash ADC.  
Input Common Mode  
The analog inputs of the AD9629 are not internally dc-biased.  
Therefore, in ac-coupled applications, the user must provide a  
dc bias externally. Setting the device so that VCM = AVDD/2  
is recommended for optimum performance, but the device can  
function over a wider range with reasonable performance, as  
shown in Figure 35 and Figure 36.  
An on-board, common-mode voltage reference is included in  
the design and is available from the VCM pin. The VCM pin  
must be decoupled to ground by a 0.1 μF capacitor, as described  
in the Applications Information section.  
The output staging block aligns the data, corrects errors, and  
passes the data to the CMOS output buffers. The output buffers  
are powered from a separate (DRVDD) supply, allowing adjust-  
ment of the output voltage swing. During power-down, the output  
buffers go into a high impedance state.  
100  
SFDR (dBc)  
ANALOG INPUT CONSIDERATIONS  
90  
80  
The analog input to the AD9629 is a differential switched-  
capacitor circuit designed for processing differential input  
signals. This circuit can support a wide common-mode range  
while maintaining excellent performance. By using an input  
common-mode voltage of midsupply, users can minimize  
signal-dependent errors and achieve optimum performance.  
SNR (dBFS)  
70  
60  
50  
H
CPAR  
H
0.5  
0.6  
0.7  
0.8  
0.9  
1.0  
1.1  
1.2  
1.3  
VIN+  
INPUT COMMON-MODE VOLTAGE (V)  
CSAMPLE  
S
S
S
S
Figure 35. SNR/SFDR vs. Input Common-Mode Voltage,  
f
IN = 32.1 MHz, fS = 80 MSPS  
CSAMPLE  
100  
90  
VIN–  
H
CPAR  
SFDR (dBc)  
H
Figure 34. Switched-Capacitor Input Circuit  
80  
The clock signal alternately switches the input circuit between  
sample-and-hold mode (see Figure 34). When the input circuit  
is switched to sample mode, the signal source must be capable  
of charging the sample capacitors and settling within one-half  
of a clock cycle. A small resistor in series with each input can  
help reduce the peak transient current injected from the output  
stage of the driving source. In addition, low Q inductors or ferrite  
beads can be placed on each leg of the input to reduce high dif-  
ferential capacitance at the analog inputs and, therefore, achieve  
the maximum bandwidth of the ADC. Such use of low Q inductors  
or ferrite beads is required when driving the converter front end at  
SNR (dBFS)  
70  
60  
50  
0.5  
0.6  
0.7  
0.8  
0.9  
1.0  
1.1  
1.2  
1.3  
INPUT COMMON-MODE VOLTAGE (V)  
Figure 36. SNR/SFDR vs. Input Common-Mode Voltage,  
fIN = 10.3 MHz, fS = 20 MSPS  
Rev. 0 | Page 17 of 32  
 
 
 
 
 
AD9629  
Differential Input Configurations  
~10 MHz where SNR is a key parameter, differential double balun  
coupling is the recommended input configuration (see Figure 40).  
Optimum performance is achieved while driving the AD9629 in a  
differential input configuration. For baseband applications, the  
AD8138, ADA4937-2, and ADA4938-2 differential drivers provide  
excellent performance and a flexible interface to the ADC.  
An alternative to using a transformer-coupled input at frequencies  
in the second Nyquist zone is to use the AD8352 differential driver.  
An example is shown in Figure 41. See the AD8352 data sheet  
for more information.  
The output common-mode voltage of the ADA4938-2 is easily  
set with the VCM pin of the AD9629 (see Figure 37), and the  
driver can be configured in a Sallen-Key filter topology to  
provide band limiting of the input signal.  
In any configuration, the value of Shunt Capacitor C is dependent  
on the input frequency and source impedance and may need to  
be reduced or removed. Table 9 displays the suggested values to set  
the RC network. However, these values are dependent on the  
input signal and should be used only as a starting guide.  
200  
33Ω  
VIN–  
VIN  
76.8Ω  
AVDD  
90Ω  
10pF  
ADC  
ADA4938  
Table 9. Example RC Network  
0.1µF  
120Ω  
33Ω  
VCM  
VIN+  
R Series  
200Ω  
Frequency Range (MHz)  
0 to 70  
(Ω Each)  
C Differential (pF)  
Figure 37. Differential Input Configuration Using the ADA4938-2  
33  
22  
70 to 200  
125  
Open  
For baseband applications below ~10 MHz where SNR is a key  
parameter, differential transformer-coupling is the recommended  
input configuration. An example is shown in Figure 38. To bias  
the analog input, the VCM voltage can be connected to the  
center tap of the secondary winding of the transformer.  
Single-Ended Input Configuration  
A single-ended input can provide adequate performance in  
cost-sensitive applications. In this configuration, SFDR and  
distortion performance degrade due to the large input common-  
mode swing. If the source impedances on each input are matched,  
there should be little effect on SNR performance. Figure 39  
shows a typical single-ended input configuration.  
VIN+  
R
2V p-p  
49.9Ω  
C
ADC  
R
VCM  
VIN–  
10µF  
AVDD  
0.1µF  
1kΩ  
R
Figure 38. Differential Transformer-Coupled Configuration  
VIN+  
1V p-p  
0.1µF  
49.9Ω  
1kΩ  
The signal characteristics must be considered when selecting  
a transformer. Most RF transformers saturate at frequencies  
below a few megahertz (MHz). Excessive signal power can  
also cause core saturation, which leads to distortion.  
AVDD  
ADC  
C
1kΩ  
R
VIN–  
10µF  
0.1µF  
1kΩ  
At input frequencies in the second Nyquist zone and above, the  
noise performance of most amplifiers is not adequate to achieve  
the true SNR performance of the AD9629. For applications above  
Figure 39. Single-Ended Input Configuration  
0.1µF  
R
R
0.1µF  
VIN+  
2V p-p  
25  
25Ω  
P
A
S
S
P
C
ADC  
0.1µF  
0.1µF  
VCM  
VIN–  
Figure 40. Differential Double Balun Input Configuration  
V
CC  
0.1µF  
0  
0.1µF  
16  
1
8, 13  
11  
0.1µF  
0.1µF  
ANALOG INPUT  
R
R
VIN+  
VIN–  
2
200Ω  
C
ADC  
AD8352  
10  
R
R
G
C
D
D
3
4
5
200Ω  
VCM  
14  
0.1µF  
ANALOG INPUT  
0Ω  
0.1µF  
0.1µF  
Figure 41. Differential Input Configuration Using the AD8352  
Rev. 0 | Page 18 of 32  
 
 
 
 
 
 
AD9629  
External Reference Operation  
VOLTAGE REFERENCE  
The use of an external reference may be necessary to enhance  
the gain accuracy of the ADC or improve thermal drift charac-  
teristics. Figure 44 shows the typical drift characteristics of the  
internal reference in 1.0 V mode.  
A stable and accurate 1.0 V voltage reference is built into the  
AD9629. The VREF can be configured using either the internal  
1.0 V reference or an externally applied 1.0 V reference voltage.  
The various reference modes are summarized in the sections  
that follow. The Reference Decoupling section describes the  
best practices PCB layout of the reference.  
4
3
Internal Reference Connection  
2
VREF ERROR (mV)  
1
0
A comparator within the AD9629 detects the potential at the  
SENSE pin and configures the reference into two possible modes,  
which are summarized in Table 10. If SENSE is grounded, the  
reference amplifier switch is connected to the internal resistor  
divider (see Figure 42), setting VREF to 1.0 V.  
–1  
–2  
–3  
–4  
–5  
–6  
VIN+  
VIN–  
ADC  
CORE  
–40  
–20  
0
20  
40  
60  
80  
TEMPERATURE (°C)  
Figure 44. Typical VREF Drift  
VREF  
When the SENSE pin is tied to AVDD, the internal reference is  
disabled, allowing the use of an external reference. An internal  
reference buffer loads the external reference with an equivalent  
7.5 kΩ load (see Figure 27). The internal buffer generates the  
positive and negative full-scale references for the ADC core.  
Therefore, the external reference must be limited to a maximum  
of 1.0 V.  
1.0µF  
0.1µF  
SELECT  
LOGIC  
SENSE  
0.5V  
ADC  
Figure 42. Internal Reference Configuration  
If the internal reference of the AD9629 is used to drive multiple  
converters to improve gain matching, the loading of the reference  
by the other converters must be considered. Figure 43 shows  
how the internal reference voltage is affected by loading.  
0
–0.5  
–1.0  
INTERNAL VREF = 0.996V  
–1.5  
–2.0  
–2.5  
–3.0  
0
0.2  
0.4  
0.6  
0.8  
1.0  
1.2  
1.4  
1.6  
1.8  
2.0  
LOAD CURRENT (mA)  
Figure 43. VREF Accuracy vs. Load Current  
Table 10. Reference Configuration Summary  
Selected Mode  
SENSE Voltage (V) Resulting VREF (V)  
Resulting Differential Span (V p-p)  
Fixed Internal Reference  
Fixed External Reference  
AGND to 0.2  
AVDD  
1.0 internal  
1.0 applied to external VREF pin  
2.0  
2.0  
Rev. 0 | Page 19 of 32  
 
 
 
 
 
AD9629  
This limit helps prevent the large voltage swings of the clock  
from feeding through to other portions of the AD9629 while  
preserving the fast rise and fall times of the signal that are critical  
to a low jitter performance.  
CLOCK INPUT CONSIDERATIONS  
For optimum performance, clock the AD9629 sample clock inputs,  
CLK+ and CLK−, with a differential signal. The signal is typi-  
cally ac-coupled into the CLK+ and CLK− pins via a transformer  
or capacitors. These pins are biased internally (see Figure 45)  
and require no external bias.  
If a low jitter clock source is not available, another option is to  
ac couple a differential PECL signal to the sample clock input  
pins, as shown in Figure 48. The AD9510/AD9511/AD9512/  
AD9513/AD9514/AD9515/AD9516/AD9517 clock drivers  
offer excellent jitter performance.  
AVDD  
0.9V  
CLK+  
CLK–  
0.1µF  
0.1µF  
CLOCK  
INPUT  
CLK+  
2pF  
2pF  
AD951x  
PECL DRIVER  
100  
ADC  
0.1µF  
0.1µF  
CLOCK  
INPUT  
CLK–  
240Ω  
240Ω  
50kΩ  
50kΩ  
Figure 45. Equivalent Clock Input Circuit  
Clock Input Options  
Figure 48. Differential PECL Sample Clock (Up to 4× Rated Sample Rate)  
The AD9629 has a very flexible clock input structure. The clock  
input can be a CMOS, LVDS, LVPECL, or sine wave signal.  
Regardless of the type of signal being used, clock source jitter is  
of great concern, as described in the Jitter Considerations section.  
A third option is to ac couple a differential LVDS signal to the  
sample clock input pins, as shown in Figure 49. The AD9510/  
AD9511/AD9512/AD9513/AD9514/AD9515/AD9516/AD9517  
clock drivers offer excellent jitter performance.  
Figure 46 and Figure 47 show two preferred methods for clock-  
ing the AD9629. The CLK inputs support up to 4× the rated  
sample rate when using the internal clock divider feature. A low  
jitter clock source is converted from a single-ended signal to a  
differential signal using either an RF transformer or an RF balun.  
0.1µF  
0.1µF  
CLOCK  
INPUT  
CLK+  
AD951x  
LVDS DRIVER  
100Ω  
ADC  
0.1µF  
0.1µF  
CLOCK  
INPUT  
CLK–  
®
50kΩ  
50kΩ  
Mini-Circuits  
ADT1-1WT, 1:1 Z  
0.1µF  
0.1µF  
XFMR  
Figure 49. Differential LVDS Sample Clock (Up to 4× Rated Sample Rate)  
CLOCK  
INPUT  
CLK+  
100  
50Ω  
In some applications, it may be acceptable to drive the sample  
clock inputs with a single-ended 1.8 V CMOS signal. In such  
applications, drive the CLK+ pin directly from a CMOS gate, and  
bypass the CLK− pin to ground with a 0.1 ꢀF capacitor (see  
Figure 50).  
ADC  
0.1µF  
CLK–  
SCHOTTKY  
DIODES:  
HSMS2822  
0.1µF  
Figure 46. Transformer-Coupled Differential Clock (3 MHz to 200 MHz)  
V
CC  
OPTIONAL  
100Ω  
0.1µF  
1
0.1µF  
1kΩ  
1kΩ  
AD951x  
CMOS DRIVER  
1nF  
50Ω  
1nF  
0.1µF  
0.1µF  
CLOCK  
INPUT  
CLK+  
CLOCK  
INPUT  
CLK+  
50Ω  
ADC  
ADC  
CLK–  
CLK–  
SCHOTTKY  
DIODES:  
0.1µF  
HSMS2822  
1
50RESISTOR IS OPTIONAL.  
Figure 47. Balun-Coupled Differential Clock (Up to 4× Rated Sample Rate)  
Figure 50. Single-Ended 1.8 V CMOS Input Clock (Up to 200 MHz)  
The RF balun configuration is recommended for clock frequencies  
between 80 MHz and 320 MHz, and the RF transformer is recom-  
mended for clock frequencies from 3 MHz to 200 MHz. The  
back-to-back Schottky diodes across the transformer/balun  
secondary limit clock excursions into the AD9629 to ~0.8 V p-p  
differential.  
Input Clock Divider  
The AD9629 contains an input clock divider with the ability  
to divide the input clock by integer values of 1, 2, or 4.  
Rev. 0 | Page 20 of 32  
 
 
 
 
 
 
 
AD9629  
Clock Duty Cycle  
The clock input should be treated as an analog signal in cases in  
which aperture jitter may affect the dynamic range of the AD9629.  
To avoid modulating the clock signal with digital noise, keep  
power supplies for clock drivers separate from the ADC output  
driver supplies. Low jitter, crystal-controlled oscillators make  
the best clock sources. If the clock is generated from another type  
of source (by gating, dividing, or another method), it should be  
retimed by the original clock at the last step.  
Typical high speed ADCs use both clock edges to generate  
a variety of internal timing signals and, as a result, may be  
sensitive to clock duty cycle. Commonly, a 50% duty cycle clock  
with 5% tolerance is required to maintain optimum dynamic  
performance as shown in Figure 51.  
Jitter on the rising edge of the clock input can also impact dynamic  
performance and should be minimized as discussed in the Jitter  
Considerations section.  
For more information, see the AN-501 Application Note and the  
AN-756 Application Note available on www.analog.com.  
80  
POWER DISSIPATION AND STANDBY MODE  
75  
70  
65  
60  
55  
50  
45  
40  
As shown in Figure 53, the analog core power dissipated by  
the AD9629 is proportional to its sample rate. The digital  
power dissipation of the CMOS outputs are determined  
primarily by the strength of the digital drivers and the load  
on each output bit.  
The maximum DRVDD current (IDRVDD) can be calculated as  
IDRVDD = VDRVDD × CLOAD × fCLK × N  
where N is the number of output bits (13, in the case of the  
AD9629).  
10  
20  
30  
40  
50  
60  
70  
80  
This maximum current occurs when every output bit switches  
on every clock cycle, that is, a full-scale square wave at the Nyquist  
frequency of fCLK/2. In practice, the DRVDD current is estab-  
lished by the average number of output bits switching, which  
is determined by the sample rate and the characteristics of the  
analog input signal.  
POSITIVE DUTY CYCLE (%)  
Figure 51. SNR vs. Clock Duty Cycle  
Jitter Considerations  
High speed, high resolution ADCs are sensitive to the quality  
of the clock input. The degradation in SNR from the low fre-  
quency SNR (SNRLF) at a given input frequency (fINPUT) due to  
jitter (tJRMS) can be calculated by  
Reducing the capacitive load presented to the output drivers  
can minimize digital power consumption. The data in Figure 53  
was taken using the same operating conditions as those used for  
the Typical Performance Characteristics, with a 5 pF load on  
each output driver.  
SNRHF = −10 log[(2π × fINPUT × tJRMS)2 + 10 (SNR /10)  
]
LF  
In the previous equation, the rms aperture jitter represents the  
clock input jitter specification. IF undersampling applications  
are particularly sensitive to jitter, as illustrated in Figure 52.  
85  
80  
80  
AD9231-80  
75  
75  
70  
65  
0.05ps  
0.2ps  
70  
65  
60  
55  
50  
45  
40  
35  
AD9231-65  
60  
55  
50  
0.5ps  
AD9231-40  
1.0ps  
1.5ps  
AD9231-20  
20  
2.0ps  
2.5ps  
10  
30  
40  
50  
60  
70  
80  
3.0ps  
CLOCK RATE (MSPS)  
45  
1
10  
100  
1k  
Figure 53. Analog Core Power vs. Clock Rate  
FREQUENCY (MHz)  
Figure 52. SNR vs. Input Frequency and Jitter  
Rev. 0 | Page 21 of 32  
 
 
 
 
 
AD9629  
In SPI mode, the AD9629 can be placed in power-down mode  
directly via the SPI port, or by using the programmable external  
MODE pin. In non-SPI mode, power-down is achieved by  
asserting the PDWN pin high. In this state, the ADC typically  
dissipates 500 μW. During power-down, the output drivers are  
placed in a high impedance state. Asserting PDWN low (or the  
MODE pin in SPI mode) returns the AD9629 to its normal  
operating mode. Note that PDWN is referenced to the digital  
output driver supply (DRVDD) and should not exceed that  
supply voltage.  
As detailed in the AN-877 Application Note, Interfacing to High  
Speed ADCs via SPI, the data format can be selected for offset  
binary, twos complement, or gray code when using the SPI control.  
Table 11. SCLK/DFS and SDIO/PDWN Mode Selection  
(External Pin Mode)  
Voltage at Pin SCLK/DFS  
SDIO/PDWN  
AGND  
Offset binary (default) Normal operation  
(default)  
DRVDD  
Twos complement  
Outputs disabled  
Low power dissipation in power-down mode is achieved by  
shutting down the reference, reference buffer, biasing networks,  
and clock. Internal capacitors are discharged when entering power-  
down mode and then must be recharged when returning to normal  
operation. As a result, wake-up time is related to the time spent  
in power-down mode, and shorter power-down cycles result in  
proportionally shorter wake-up times.  
Digital Output Enable Function (OEB)  
When using the SPI interface, the data outputs and DCO can be  
independently three-stated by using the programmable external  
MODE pin. The MODE pin (OEB) function is enabled via  
Bits[6:5] of Register 0x08.  
If the MODE pin is configured to operate in traditional OEB  
mode and the OEB pin is low, the output data drivers and  
DCOs are enabled. If the OEB pin is high, the output data  
drivers and DCOs are placed in a high impedance state. This  
OEB function is not intended for rapid access to the data bus.  
Note that OEB is referenced to the digital output driver supply  
(DRVDD) and should not exceed that supply voltage.  
When using the SPI port interface, the user can place the ADC  
in power-down mode or standby mode. Standby mode allows  
the user to keep the internal reference circuitry powered when  
faster wake-up times are required. See the Memory Map section  
for more details.  
DIGITAL OUTPUTS  
TIMING  
The AD9629 output drivers can be configured to interface with  
1.8 V to 3.3 V CMOS logic families. Output data can also be  
multiplexed onto a single output bus to reduce the total number  
of traces required.  
The AD9629 provides latched data with a pipeline delay of  
9 clock cycles. Data outputs are available one propagation  
delay (tPD) after the rising edge of the clock signal.  
Minimize the length of the output data lines and loads placed  
on them to reduce transients within the AD9629. These  
transients can degrade converter dynamic performance.  
The CMOS output drivers are sized to provide sufficient output  
current to drive a wide variety of logic families. However, large  
drive currents tend to cause current glitches on the supplies and  
may affect converter performance.  
The lowest typical conversion rate of the AD9629 is 3 MSPS. At  
clock rates below 3 MSPS, dynamic performance can degrade.  
Applications requiring the ADC to drive large capacitive loads  
or large fanouts may require external buffers or latches.  
Data Clock Output (DCO)  
The AD9629 provides a data clock output (DCO) signal  
intended for capturing the data in an external register. The CMOS  
data outputs are valid on the rising edge of DCO, unless the DCO  
clock polarity has been changed via the SPI. See Figure 2 for a  
graphical timing description.  
The output data format can be selected to be either offset binary  
or twos complement by setting the SCLK/DFS pin when operating  
in the external pin mode (see Table 11).  
Table 12. Output Data Format  
Input (V)  
Condition (V)  
< −VREF − 0.5 LSB  
= −VREF  
Offset Binary Output Mode  
0000 0000 0000  
0000 0000 0000  
1000 0000 0000  
1111 1111 1111  
Twos Complement Mode  
1000 0000 0000  
1000 0000 0000  
0000 0000 0000  
0111 1111 1111  
OR  
1
0
0
0
VIN+ − VIN−  
VIN+ − VIN−  
VIN+ − VIN−  
VIN+ − VIN−  
VIN+ − VIN−  
= 0  
= +VREF − 1.0 LSB  
> +VREF − 0.5 LSB  
1111 1111 1111  
0111 1111 1111  
1
Rev. 0 | Page 22 of 32  
 
 
 
 
AD9629  
BUILT-IN SELF-TEST (BIST) AND OUTPUT TEST  
generator, Bit 2 (BIST INIT) of Register 0x0E. At the completion  
The AD9629 includes a built-in self-test feature designed to  
enable verification of the integrity of each channel as well as to  
facilitate board level debugging. A built-in self-test (BIST) feature  
that verifies the integrity of the digital datapath of the AD9629  
is included. Various output test options are also provided to place  
predictable values on the outputs of the AD9629.  
of the BIST, Bit 0 of Register 0x24 is automatically cleared. The PN  
sequence can be continued from its last value by writing a 0 in  
Bit 2 of Register 0x0E. However, if the PN sequence is not reset,  
the signature calculation does not equal the predetermined  
value at the end of the test. At that point, the user needs to rely  
on verifying the output data.  
BUILT-IN SELF-TEST (BIST)  
OUTPUT TEST MODES  
The BIST is a thorough test of the digital portion of the selected  
AD9629 signal path. Perform the BIST test after a reset to ensure  
the part is in a known state. During BIST, data from an internal  
pseudorandom noise (PN) source is driven through the digital  
datapath of both channels, starting at the ADC block output.  
At the datapath output, CRC logic calculates a signature from  
the data. The BIST sequence runs for 512 cycles and then stops.  
Once completed, the BIST compares the signature results with a  
predetermined value. If the signatures match, the BIST sets Bit 0  
of Register 0x24, signifying the test passed. If the BIST test failed,  
Bit 0 of Register 0x24 is cleared. The outputs are connected  
during this test, so the PN sequence can be observed as it runs.  
Writing 0x05 to Register 0x0E runs the BIST. This enables the Bit 0  
(BIST enable) of Register 0x0E and resets the PN sequence  
The output test options are described in Table 16 at Address  
0x0D. When an output test mode is enabled, the analog section  
of the ADC is disconnected from the digital back-end blocks  
and the test pattern is run through the output formatting block.  
Some of the test patterns are subject to output formatting, and  
some are not. The PN generators from the PN sequence tests  
can be reset by setting Bit 4 or Bit 5 of Register 0x0D. These  
tests can be performed with or without an analog signal (if  
present, the analog signal is ignored), but they do require an  
encode clock. For more information, see the AN-877  
Application Note, Interfacing to High Speed ADCs via SPI.  
Rev. 0 | Page 23 of 32  
 
 
AD9629  
SERIAL PORT INTERFACE (SPI)  
The falling edge of CSB, in conjunction with the rising edge of  
SCLK, determines the start of the framing. An example of the  
serial timing and its definitions can be found in Figure 54 and  
Table 5.  
The AD9629 serial port interface (SPI) allows the user to configure  
the converter for specific functions or operations through a  
structured register space provided inside the ADC. The SPI  
gives the user added flexibility and customization, depending  
on the application. Addresses are accessed via the serial port  
and can be written to or read from via the port. Memory is  
organized into bytes that can be further divided into fields,  
which are documented in the Memory Map section. For  
detailed operational information, see the AN-877 Application  
Note, Interfacing to High Speed ADCs via SPI.  
Other modes involving the CSB are available. The CSB can be  
held low indefinitely, which permanently enables the device;  
this is called streaming. The CSB can stall high between bytes to  
allow for additional external timing. When CSB is tied high, SPI  
functions are placed in high impedance mode. This mode turns  
on any SPI pin secondary functions.  
During an instruction phase, a 16-bit instruction is transmitted.  
Data follows the instruction phase, and its length is determined  
by the W0 and W1 bits as shown in Figure 54.  
CONFIGURATION USING THE SPI  
Three pins define the SPI of this ADC: the SCLK, the SDIO,  
and the CSB (see Table 13). The SCLK (a serial clock) is used  
to synchronize the read and write data presented from and to  
the ADC. The SDIO (serial data input/output) is a dual-purpose  
pin that allows data to be sent and read from the internal ADC  
memory map registers. The CSB (chip select bar) is an active-  
low control that enables or disables the read and write cycles.  
All data is composed of 8-bit words. The first bit of the first byte in  
a multibyte serial data transfer frame indicates whether a read  
command or a write command is issued. This allows the serial  
data input/output (SDIO) pin to change direction from an input  
to an output at the appropriate point in the serial frame.  
In addition to word length, the instruction phase determines  
whether the serial frame is a read or write operation, allowing  
the serial port to be used both to program the chip and to read  
the contents of the on-chip memory. If the instruction is a readback  
operation, performing a readback causes the serial data input/  
output (SDIO) pin to change direction from an input to an output  
at the appropriate point in the serial frame.  
Table 13. Serial Port Interface Pins  
Pin  
Function  
SCLK Serial clock. The serial shift clock input, which is used to  
synchronize serial interface reads and writes.  
SDIO Serial data input/output. A dual-purpose pin that  
typically serves as an input or an output, depending on  
the instruction being sent and the relative position in the  
timing frame.  
Data can be sent in MSB-first mode or in LSB-first mode. MSB  
first is the default on power-up and can be changed via the SPI  
port configuration register. For more information about this  
and other features, see the AN-877 Application Note, Interfacing  
to High Speed ADCs via SPI.  
CSB  
Chip select bar. An active-low control that gates the read  
and write cycles.  
tHIGH  
tDS  
tCLK  
tH  
tS  
tDH  
tLOW  
CSB  
SCLK DON’T CARE  
SDIO DON’T CARE  
DON’T CARE  
R/W  
W1  
W0  
A12  
A11  
A10  
A9  
A8  
A7  
D5  
D4  
D3  
D2  
D1  
D0  
DON’T CARE  
Figure 54. Serial Port Interface Timing Diagram  
Rev. 0 | Page 24 of 32  
 
 
 
 
AD9629  
HARDWARE INTERFACE  
CONFIGURATION WITHOUT THE SPI  
The pins described in Table 13 constitute the physical interface  
between the programming device of the user and the serial  
port of the AD9629. The SCLK pin and the CSB pin function  
as inputs when using the SPI interface. The SDIO pin is  
bidirectional, functioning as an input during write phases  
and as an output during readback.  
In applications that do not interface to the SPI control registers,  
the SDIO/PDWN pin, the SCLK/DFS pin serve as standalone  
CMOS-compatible control pins. When the device is powered up, it  
is assumed that the user intends to use the pins as static control  
lines for the power-down and output data format feature control.  
In this mode, connect the CSB chip select to DRVDD, which  
disables the serial port interface.  
The SPI interface is flexible enough to be controlled by  
either FPGAs or microcontrollers. One method for SPI  
configuration is described in detail in the AN-812 Appli-  
cation Note, Microcontroller-Based Serial Port Interface  
(SPI) Boot Circuit.  
Table 14. Mode Selection  
External  
Pin  
SDIO/PDWN DRVDD  
AGND (default)  
DRVDD  
AGND (default)  
Voltage  
Configuration  
Chip power-down mode  
Normal operation(default)  
Twos complement enabled  
Offset binary enabled  
The SPI port should not be active during periods when the full  
dynamic performance of the converter is required. Because the  
SCLK signal, the CSB signal, and the SDIO signal are typically  
asynchronous to the ADC clock, noise from these signals can  
degrade converter performance. If the on-board SPI bus is used for  
other devices, it may be necessary to provide buffers between  
this bus and the AD9629 to prevent these signals from transi-  
tioning at the converter inputs during critical sampling periods.  
SCLK/DFS  
SPI ACCESSIBLE FEATURES  
Table 15 provides a brief description of the general features that  
are accessible via the SPI. These features are described in detail  
in the AN-877 Application Note, Interfacing to High Speed ADCs  
via SPI. The AD9629 part-specific features are described in  
detail in Table 16.  
SDIO/PDWN and SCLK/DFS serve a dual function when the  
SPI interface is not being used. When the pins are strapped to  
DRVDD or ground during device power-on, they are associated  
with a specific function. The Digital Outputs section describes  
the strappable functions supported on the AD9629.  
Table 15. Features Accessible Using the SPI  
Feature  
Description  
Modes  
Allows the user to set either power-down mode or  
standby mode  
Offset Adjust Allows the user to digitally adjust the converter  
offset  
Test Mode  
Allows the user to set test modes to have known  
data on output bits  
Output Mode Allows the user to set up outputs  
Output Phase Allows the user to set the output clock polarity  
Output Delay Allows the user to vary the DCO delay  
Rev. 0 | Page 25 of 32  
 
 
 
 
AD9629  
MEMORY MAP  
READING THE MEMORY MAP REGISTER TABLE  
DEFAULT VALUES  
Each row in the memory map register table (see Table 16)  
contains eight bit locations. The memory map is roughly  
divided into four sections: the chip configuration registers  
(Address 0x00 to Address 0x02); the device transfer register  
(Address 0xFF); the program registers, including setup, control,  
and test (Address 0x08 to Address 0x2A); and the AD9629  
specific customer SPI control register (Address 0x101).  
After the AD9629 is reset, critical registers are loaded with default  
values. The default values for the registers are given in the memory  
map register table (see Table 16).  
Logic Levels  
An explanation of logic level terminology follows:  
“Bit is set” is synonymous with “bit is set to Logic 1” or  
“writing Logic 1 for the bit.”  
Table 16 documents the default hexadecimal value for each  
“Clear a bit” is synonymous with “bit is set to Logic 0” or  
“writing Logic 0 for the bit.”  
hexadecimal address shown. The column with the heading Bit 7  
(MSB) is the start of the default hexadecimal value given. For  
example, Address 0x2A, the OR/MODE select register, has a hexa-  
decimal default value of 0x01. This means that in Address 0x2A,  
Bits[7:1] = 0, and Bit 0 = 1. This setting is the default OR/MODE  
setting. The default value results in the programmable external  
MODE/OR pin (Pin 23) functioning as an out-of-range digital  
output. For more information on this function and others, see the  
AN-877 Application Note, Interfacing to High Speed ADCs via SPI.  
This application note details the functions controlled by Register  
0x00 to Register 0xFF. The remaining register, Register 0x101, is  
documented in the Memory Map section that follows Table 16.  
Transfer Register Map  
Address 0x08 to Address 0x18 are shadowed. Writes to these  
addresses do not affect part operation until a transfer command  
is issued by writing 0x01 to Address 0xFF, setting the transfer bit.  
This allows these registers to be updated internally and simulta-  
neously when the transfer bit is set. The internal update takes  
place when the transfer bit is set, and then the bit autoclears.  
OPEN LOCATIONS  
All address and bit locations that are not included in the SPI map  
are not currently supported for this device. Unused bits of a valid  
address location should be written with 0s. Writing to these loca-  
tions is required only when part of an address location is open  
(for example, Address 0x2A). If the entire address location is  
open, it is omitted from the SPI map (for example, Address 0x13)  
and should not be written.  
Rev. 0 | Page 2ꢀ of 32  
 
 
 
 
AD9629  
MEMORY MAP REGISTER TABLE  
All address and bit locations that are not included in Table 16 are not currently supported for this device.  
Table 16.  
Default  
Value  
(Hex)  
Addr  
Bit 7  
(MSB)  
Bit 0  
(LSB)  
(Hex) Register Name  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Comments  
Chip Configuration Registers  
0x00  
SPI port  
configuration  
0
LSB  
first  
Soft  
reset  
1
1
Soft reset  
LSB  
first  
0
0x18  
The nibbles are  
mirrored so that LSB  
or MSB first mode  
registers correctly,  
regardless of shift  
mode  
0x01  
0x02  
Chip ID  
8-bit chip ID, Bits[7:0]  
AD9ꢀ29 = 0x70  
Read  
only  
Unique chip ID used  
to differentiate  
devices; read only  
Chip grade  
Open  
Speed grade ID, Bits[ꢀ:4]  
(identify device variants of  
chip ID)  
Open  
Read  
only  
Unique speed grade  
ID used to  
differentiate devices;  
Read only  
20 MSPS = 000  
40 MSPS = 001  
ꢀ5 MSPS = 010  
80 MSPS = 011  
Device Index and Transfer Register  
0xFF Transfer Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open Transfer  
0x00  
0x00  
Synchronously  
transfers data from  
the master shift  
register to the slave  
Program Registers  
0x08  
Modes  
External External Pin 23  
00 = chip run  
01 = full power down  
10 = standby  
11 = chip wide digital  
reset  
Determines various  
generic modes of  
chip operation  
Pin 23  
mode  
input  
function when high  
00 = full power  
down  
01 = standby  
10 = normal  
mode: output  
disabled  
enable  
11 = normal  
mode: output  
enabled  
0x0B  
0x0D  
Clock divide  
Test mode  
Open  
Clock divider, Bits[2:0]  
0x00  
0x00  
The divide ratio is  
the value plus 1  
Clock divide ratio  
000 = divide-by-1  
001 = divide-by-2  
011 = divide-by-4  
User test mode  
00 = single  
01 = alternate  
10 = single once  
11 = alternate  
once  
Reset PN Reset  
long gen PN  
short  
Output test mode, Bits[3:0] (local)  
0000 = off (default)  
0001 = midscale short  
0010 = positive FS  
When set, the test  
data is placed on the  
output pins in place  
of normal data  
gen  
0011 = negative FS  
0100 = alternating checkerboard  
0101 = PN 23 sequence  
0110 = PN 9 sequence  
0111 = 1/0 word toggle  
1000 = user input  
1001 = one/zero bit toggle  
1010 = 1× sync  
1011 = one bit high  
1100 = mixed bit frequency  
0x0E  
0x10  
BIST enable  
Offset adjust  
Open  
Open  
Open  
Open  
Open  
BIST INIT  
Open BIST enable  
0x00  
0x00  
When Bit 0 is set, the  
built-in self-test  
function is initiated  
8-bit device offset adjustment [7:0] (local)  
Device offset trim  
Offset adjust in LSBs from +127 to −128 (twos complement format)  
Rev. 0 | Page 27 of 32  
 
 
AD9629  
Default  
Value  
(Hex)  
Addr  
Bit 7  
(MSB)  
Bit 0  
(LSB)  
(Hex) Register Name  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Comments  
0x14  
Output mode  
00 = 3.3 V CMOS  
10 = 1.8 V CMOS  
Open  
Output Open  
disable  
Output  
invert  
00 = offset binary  
01 = twos  
complement  
0x00  
Configures the  
outputs and the  
format of the data  
10 = gray code  
11 = offset binary  
0x15  
Output adjust  
3.3 V DCO  
1.8 V DCO  
3.3 V data  
1.8 V data  
0x22  
Determines CMOS  
output drive  
strength properties  
drive strength  
00 = 1 stripe  
(default)  
01 = 2 stripes  
10 = 3 stripes  
11 = 4 stripes  
drive strength  
00 = 1 stripe  
01 = 2 stripes  
10 = 3 stripes  
(default)  
drive strength  
00 = 1 stripe  
(default)  
01 = 2 stripes  
10 = 3 stripes  
11 = 4 stripes  
drive strength  
00 = 1 stripe  
01 = 2 stripes  
10 = 3 stripes  
(default)  
11 = 4 stripes  
11 = 4 stripes  
0x1ꢀ  
Output phase  
DCO  
Open  
Open  
Open  
Open  
Input clock phase adjust, Bits[2:0]  
(Value is number of input clock  
cycles of phase delay)  
0x00  
On devices that  
utilize global clock  
divide, determines  
which phase of the  
divider output is  
used to supply the  
output clock;  
Output  
polarity  
0 =  
normal  
1 =  
000 = no delay  
001 = 1 input clock cycle  
010 = 2 input clock cycles  
011 = 3 input clock cycles  
100 = 4 input clock cycles  
101 = 5 input clock cycles  
110 = ꢀ input clock cycles  
111 = 7 input clock cycles  
inverted  
internal latching is  
unaffected  
0x17  
Output delay  
Enable  
DCO  
delay  
Open  
Enable  
data  
delay  
Open  
DCO/data delay, Bits[2:0]  
000 = 0.5ꢀ ns  
001 = 1.12 ns  
010 = 1.ꢀ8 ns  
011 = 2.24 ns  
100 = 2.80 ns  
101 = 3.3ꢀ ns  
110 = 3.92 ns  
111 = 4.48 ns  
0x00  
Sets the fine output  
delay of the output  
clock, but does not  
change internal  
timing  
0x19  
0x1A  
0x1B  
0x1C  
0x24  
USER_PATT1_LSB  
B7  
Bꢀ  
B5  
B4  
B3  
B2  
B1  
B9  
B1  
B9  
B0  
B8  
B0  
B8  
0x00  
0x00  
0x00  
0x00  
0x00  
User-defined  
pattern, 1 LSB  
USER_PATT1_MSB B15  
USER_PATT2_LSB B7  
B14  
Bꢀ  
B13  
B5  
B12  
B4  
B11  
B3  
B10  
B2  
User-defined  
pattern, 1 MSB  
User-defined  
pattern, 2 LSB  
USER_PATT2_MSB B15  
BIST signature LSB  
B14  
B13  
B12  
B11  
B10  
User-defined  
pattern, 2 MSB  
BIST signature, Bits[7:0]  
Least significant byte  
of BIST signature,  
read only  
0x2A  
OR/MODE select  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
Open  
0 =  
0x01  
Selects I/O  
MODE  
1 = OR  
(default)  
functionality in  
conjunction w/  
Address 0x08 for  
MODE (input) or OR  
(output) on external  
Pin 23  
1.1. AD9ꢀ29 Specific Customer SPI Control  
0x101 USR2  
1
Enable  
GCLK  
detect  
Run GCLK  
Disable  
SDIO  
pull-  
0x88  
Enables internal  
oscillator for clock  
rates of <5 MHz  
down  
Rev. 0 | Page 28 of 32  
AD9629  
Bit 2—Run GCLK  
MEMORY MAP REGISTER DESCRIPTIONS  
This bit enables the GCLK oscillator. For some applications  
with encode rates below 10 MSPS, it may be preferable to set  
this bit high to supersede the GCLK detector.  
For additional information about functions controlled in  
Register 0x00 to Register 0xFF, see the AN-877 Application  
Note, Interfacing to High Speed ADCs via SPI.  
Bit 0—Disable SDIO Pull-Down  
USR2 (Register 0x101)  
This bit can be set high to disable the internal 30 kꢁ pull-down  
on the SDIO pin, which can be used to limit the loading when  
many devices are connected to the SPI bus.  
Bit 3—Enable GCLK Detect  
Normally set high, this bit enables a circuit that detects encode  
rates below about 5 MSPS. When a low encode rate is detected,  
an internal oscillator, GCLK, is enabled ensuring the proper  
operation of several circuits. If set low the detector is disabled.  
Rev. 0 | Page 29 of 32  
 
AD9629  
APPLICATIONS INFORMATION  
To maximize the coverage and adhesion between the ADC and  
the PCB, a silkscreen should be overlaid to partition the continuous  
plane on the PCB into several uniform sections. This provides  
several tie points between the ADC and the PCB during the reflow  
process. Using one continuous plane with no partitions guarantees  
only one tie point between the ADC and the PCB. For detailed  
information about packaging and PCB layout of chip scale  
packages, see the AN-772 Application Note, A Design and  
Manufacturing Guide for the Lead Frame Chip Scale Package  
(LFCSP), at www.analog.com.  
DESIGN GUIDELINES  
Before starting design and layout of the AD9629 as a system,  
it is recommended that the designer become familiar with these  
guidelines, which discuss the special circuit connections and  
layout requirements needed for certain pins.  
Power and Ground Recommendations  
When connecting power to the AD9629, it is strongly recom-  
mended that two separate supplies be used. Use one 1.8 V supply  
for analog (AVDD); use a separate 1.8 V to 3.3 V supply for the  
digital output supply (DRVDD). If a common 1.8 V AVDD and  
DRVDD supply must be used, the AVDD and DRVDD domains  
must be isolated with a ferrite bead or filter choke and separate  
decoupling capacitors. Several different decoupling capacitors  
can be used to cover both high and low frequencies. Locate  
these capacitors close to the point of entry at the PCB level  
and close to the pins of the part, with minimal trace length.  
Encode Clock  
For optimum dynamic performance a low jitter encode clock  
source with a 50% duty cycle 5% should be used to clock the  
AD9629.  
VCM  
The VCM pin should be decoupled to ground with a 0.1 ꢀF  
capacitor, as shown in Figure 38.  
A single PCB ground plane should be sufficient when using the  
AD9629. With proper decoupling and smart partitioning of the  
PCB analog, digital, and clock sections, optimum performance  
is easily achieved.  
RBIAS  
The AD9629 requires that a 10 kΩ resistor be placed between  
the RBIAS pin and ground. This resistor sets the master current  
reference of the ADC core and should have at least a 1% tolerance.  
Exposed Paddle Thermal Heat Sink Recommendations  
The exposed paddle (Pin 0) is the only ground connection for  
the AD9629; therefore, it must be connected to analog ground  
(AGND) on the customers PCB. To achieve the best electrical  
and thermal performance, mate an exposed (no solder mask)  
continuous copper plane on the PCB to the AD9629 exposed  
paddle, Pin 0.  
Reference Decoupling  
Externally decouple the VREF pin to ground with a low ESR,  
1.0 ꢀF capacitor in parallel with a low ESR, 0.1 ꢀF ceramic  
capacitor.  
SPI Port  
The SPI port should not be active during periods when the full  
dynamic performance of the converter is required. Because the  
SCLK, CSB, and SDIO signals are typically asynchronous to the  
ADC clock, noise from these signals can degrade converter  
performance. If the on-board SPI bus is used for other devices,  
it may be necessary to provide buffers between this bus and the  
AD9629 to keep these signals from transitioning at the converter  
inputs during critical sampling periods.  
The copper plane should have several vias to achieve the  
lowest possible resistive thermal path for heat dissipation to  
flow through the bottom of the PCB. Fill or plug these vias  
with nonconductive epoxy.  
Rev. 0 | Page 30 of 32  
 
 
 
 
AD9629  
OUTLINE DIMENSIONS  
5.00  
BSC SQ  
0.60 MAX  
0.60 MAX  
PIN 1  
INDICATOR  
25  
24  
32  
1
PIN 1  
INDICATOR  
0.50  
BSC  
EXPOSED  
PAD  
(BOTTOM VIEW)  
3.65  
3.50 SQ  
3.35  
TOP  
VIEW  
4.75  
BSC SQ  
0.50  
0.40  
0.30  
17  
16  
8
9
0.25 MIN  
0.80 MAX  
0.65 TYP  
3.50 REF  
12° MAX  
FOR PROPER CONNECTION OF  
THE EXPOSED PAD, REFER TO  
THE PIN CONFIGURATION AND  
FUNCTION DESCRIPTIONS  
0.05 MAX  
0.02 NOM  
1.00  
0.85  
0.80  
0.30  
0.23  
0.18  
COPLANARITY  
0.08  
SECTION OF THIS DATA SHEET.  
0.20 REF  
SEATING  
PLANE  
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2  
Figure 55. 32-Lead Lead Frame Chip Scale Package [LFCSP_VQ]  
5 mm × 5 mm Body, Very Thin Quad (CP-32-4)  
Dimensions shown in millimeters  
ORDERING GUIDE  
Model  
Temperature Range  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
–40°C to +85°C  
Package Description  
Package Option  
CP-32-4  
CP-32-4  
CP-32-4  
CP-32-4  
CP-32-4  
CP-32-4  
CP-32-4  
CP-32-4  
AD9ꢀ29BCPZ-801, 2  
AD9ꢀ29BCPZRL7-801, 2  
AD9ꢀ29BCPZ-ꢀ51, 2  
AD9ꢀ29BCPZRL7-ꢀ51, 2  
AD9ꢀ29BCPZ-401, 2  
AD9ꢀ29BCPZRL7-401, 2  
AD9ꢀ29BCPZ-201, 2  
AD9ꢀ29BCPZRL7-201, 2  
AD9ꢀ29-80EBZ1  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
32-Lead Lead Frame Chip Scale Package (LFCSP_VQ)  
Evaluation Board  
AD9ꢀ29-ꢀ5EBZ1  
Evaluation Board  
Evaluation Board  
Evaluation Board  
AD9ꢀ29-40EBZ1  
AD9ꢀ29-20EBZ1  
1 Z = RoHS Compliant Part.  
2 The exposed paddle (Pin 0) is the only GND connection on the chip and must be connected to the PCB AGND.  
Rev. 0 | Page 31 of 32  
 
 
 
AD9629  
NOTES  
©2009 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D08540-0-10/09(0)  
Rev. 0 | Page 32 of 32  

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