AD7685

Data Sheet

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

REF

1

VDD

2

IN+

3

IN–

4

GND

5

VIO

10

SDI

9

SCK

8

SDO

7

CNV

6

AD7685

TOP VIEW

(Not to Scale)

Figure 5. 10-Lead MSOP Pin Configuration

1

REF

2

VDD

3

IN+

4

IN–

5

GND

10 VIO

9

SDI

8

SCK

7

SDO

6

CNV

TOP VIEW

(Not to Scale)

AD7685

NOTES

1. EXPOSED PAD CONNECTED TO GND. THIS

CONNECTION IS NOT REQUIRED TO MEET

THE ELECTRICAL PERFORMANCES.

Figure 6. 10-Lead LFCSP Pin Configuration

Table 7. Pin Function Descriptions

Pin No

Mnemonic

Type1

Description

1

REF

AI

Reference Input Voltage. The REF range is from 0.5 V to VDD. It is referred to the GND pin. This pin should

be decoupled closely to the pin with a 10 µF capacitor.

2

VDD

P

Power Supply.

3

IN+

AI

4

IN−

AI

Analog Input Ground Sense. Connect to the analog ground plane or to a remote sense ground.

5

GND

P

Power Supply Ground.

6

CNV

DI

Convert Input. This input has multiple functions. On its leading edge, it initiates the conversions and

selects the interface mode of the part, chain, or CS mode. In CS mode, it enables the SDO pin when low.

In chain mode, the data should be read when CNV is high.

7

SDO

DO

Serial Data Output. The conversion result is output on this pin. It is synchronized to SCK.

8

SCK

DI

Serial Data Clock Input. When the part is selected, the conversion result is shifted out by this clock.

9

SDI

DI

Serial Data Input. This input provides multiple features. It selects the interface mode of the ADC as follows:

Chain mode is selected if SDI is low during the CNV rising edge. In this mode, SDI is used as a data input

to daisy chain the conversion results of two or more ADCs onto a single SDO line. The digital data level

on SDI is output on SDO with a delay of 16 SCK cycles.

CS mode is selected if SDI is high during the CNV rising edge. In this mode, either SDI or CNV can enable

the serial output signals when low, and if SDI or CNV is low when the conversion is complete, the BUSY

indicator feature is enabled.

10

VIO

P

Input/Output Interface Digital Power. Nominally at the same supply as the host interface (1.8 V, 2.5 V, 3 V, or 5 V).

EPAD

N/A

Exposed Pad. Exposed pad connected to GND. This connection is not required to meet the electrical

performances.

1

AI = analog input, DI = digital input, DO = digital output, and P = power.

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