Data Sheet

AD7381-4

Rev. 0 | Page 9 of 31

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

2

1

3

4

5

6

18

17

16

15

14

13

GND

REGCAP

GND

GND

REFCAP

GND

REFIO

CS

AD7381-4

TOP VIEW

(Not to Scale)

NOTES

1. EXPOSED PAD. THE EXPOSED PAD MUST BE

CONNECTED TO GROUND.

Figure 9. Pin Configuration

Table 8. Pin Function Descriptions

Pin No.

Mnemonic

Description

1, 5, 14, 16

GND

Ground Reference Point. These pins are the ground reference points for all circuitry on the device.

2

Logic Interface Supply Voltage, 1.65 V to 3.6 V. Decouple this pin to GND with a 1 µF capacitor.

3

REGCAP

Decoupling Capacitor Pin for Voltage Output from Internal Regulator. Decouple this pin to GND with a

1 µF capacitor. The voltage at this pin is 1.9 V typical.

4

Power Supply Input Voltage. 3.0 V to 3.6 V. Decouple this pin to GND using a 1 µF capacitor.

6, 7

Analog Inputs of ADC D. These analog inputs form a fully differential pair.

8, 9

Analog Inputs of ADC C. These analog inputs form a fully differential pair.

10, 11

Analog Inputs of ADC B. These analog inputs form a fully differential pair.

12, 13

Analog Inputs of ADC A. These analog inputs form a fully differential pair.

15

REFCAP

Decoupling Capacitor Pin for Bandgap Reference. Decouple this pin to GND with a 0.1 μF capacitor. The

voltage at this pin is 2.5 V typical. If the device is configured for external reference operation the 0.1μF

capacitor is not required.

17

REFIO

Reference Input. An external reference of 2.5 V to 3.3 V can be input to this pin. Decoupling is required

on this pin. Apply a 1 µF capacitor from this pin to GND.

18

CS

Chip Select Input. Active low, logic input. This input provides the dual function of initiating conversions

on the AD7381-4 and framing the serial data transfer.

19

SDOA

Serial Data Output A. This pin functions as a serial data output pin to access the conversion results and

register contents.

20

SDOB

Serial Data Output B. This pin functions as a serial data output pin to access the conversion results.

21

SDI

Serial Data Input. This input provides the data written to the on-chip control registers.

22

SCLK

Serial Clock Input. This serial clock input is for data transfers to and from the ADC.

23

SDOC

Serial Data Output C. This pin functions as a serial data output pin to access the conversion results and

register contents.

24

SDOD/ALERT

Serial Data Output D (SDOD). This pin functions as a serial data output to access the conversion results.

Alert Indication Output (ALERT). This pin operates as an alert going low to indicate that a conversion

result has exceeded a configured threshold.

This pin can operate as a serial data output pin or alert indication output.

Not applicable

EPAD

Exposed Pad. The exposed pad must be connected to ground.