Data Sheet

AD4684/AD4685

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

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Rev. 0 | 8 of 32

Figure 6. Pin Configuration

Table 6. Pin Function Descriptions

Pin No.

Mnemonic

Description

1, 10

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.

5, 6

Analog Inputs of ADC B.

7, 8

Analog Inputs of ADC A.

9

REFCAP

Decoupling Capacitor Pin for Band Gap 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 0.1 µF capacitor is not required.

11

REFIO

Reference Input/Output. The on-chip reference of 2.5 V is available as an output on this pin for external use if the device is

configured accordingly. Alternatively, an external reference of 2.5 V to 3.3 V can be input to this pin. The REFSEL bit in the

CONFIGURATION1 register must be set correctly when choosing the reference voltage source. Decoupling is required on this pin

for both the internal and external reference options. A 1 μF capacitor must be applied from this pin to GND.

12

CS

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

transfer.

13

SDOA

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

any of the on-chip registers.

14

SDOB/ALERT

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

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

configured threshold.

15

SDI

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

16

SCLK

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

EPAD

Exposed Pad. For correct operation of the device, the exposed pad must be connected to GND.