Data Sheet

AD9635

Rev. B | Page 11 of 36

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

Figure 8. Pin Configuration, Top View

Table 8. Pin Function Descriptions

Pin No.

Mnemonic

Description

0

AGND,

Exposed Pad

The exposed paddle is the only ground connection on the chip. It must be soldered to the analog

ground of the PCB to ensure proper functionality and heat dissipation, noise, and mechanical strength

benefits.

1, 24, 25, 28 29, 32

AVDD

1.8 V Supply Pins for ADC Analog Core Domain.

2, 3

CLK+, CLK−

Differential Encode Clock for LVPECL, LVDS, or 1.8 V CMOS Inputs.

4

SDIO/PDWN

Data Input/Output in SPI Mode (SDIO). Bidirectional SPI data I/O with 30 kΩ internal pull-down.

Power-Down in Non-SPI Mode (PDWN). Static control of chip power-down with 30 kΩ internal pull-down.

5

SCLK/DFS

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, with 30 kΩ internal

pull-down. DFS high = twos complement output; DFS low = offset binary output.

6, 19

DRVDD

1.8 V Supply Pins for Output Driver Domain.

7, 8

D1B−, D1B+

Channel B Digital Outputs.

9, 10

D0B−, D0B+

Channel B Digital Outputs.

11, 12

DCO−, DCO+

Data Clock Outputs.

13, 14

FCO−, FCO+

Frame Clock Outputs.

15, 16

D1A−, D1A+

Channel A Digital Outputs.

17, 18

D0A−, D0A+

Channel A Digital Outputs.

20

CSB

SPI Chip Select. Active low enable with 15 kΩ internal pull-up.

21

VREF

1.0 V Voltage Reference Output.

22

VCM

Analog Output Voltage at Mid AVDD Supply. Sets the common-mode voltage of the analog inputs.

23

RBIAS

Sets the analog current bias. Connect this pin to a 10 kΩ (1% tolerance) resistor to ground.

26, 27

VINA−, VINA+

Channel A ADC Analog Inputs.

30, 31

VINB+, VINB−

Channel B ADC Analog Inputs.

24 AVDD

23 RBIAS

22 VCM

21 VREF

20 CSB

19 DRVDD

18 D0A+

17 D0A–

1

2

3

4

5

6

7

8

AVDD

CLK+

CLK–

SDIO/PDWN

SCLK/DFS

DRVDD

D1B–

D1B+

AD9635

TOP VIEW

(Not to Scale)

NOTES

1. THE EXPOSED PADDLE IS THE ONLY GROUND CONNECTION

ON THE CHIP. IT MUST BE SOLDERED TO THE ANALOG GROUND

OF THE PCB TO ENSURE PROPER FUNCTIONALITY AND HEAT

DISSIPATION, NOISE, AND MECHANICAL STRENGTH BENEFITS.