AD7699

Data Sheet

Rev. F | Page 8 of 32

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

VDD

REF

REFIN

GND

GND

SCK

SDO

VIO

DIN

CNV

NOTES

1. THE EXPOSED PAD IS NOT CONNECTED

INTERNALLY. FOR INCREASED

RELIABILITY OF THE SOLDER JOINTS, IT

IS RECOMMENDED THAT THE PAD BE

SOLDERED TO THE SYSTEM

GROUND PLANE.

14

13

12

1

3

4

15

11

2

5

AD7699

TOP VIEW

(Not to Scale)

Figure 4. 20-Lead LFCSP Pin Configuration

Table 6. 20-Lead LFCSP Pin Function Descriptions

Pin No.

Mnemonic

Type1

Description

1, 20

VDD

P

Power Supply. Nominally 4.5 to 5.5 V and should be decoupled with 10 μF and 100 nF capacitors.

2

REF

AI/O

Reference Input/Output. See the Voltage Reference Output/Input section.

When the internal reference is enabled, this pin produces 4.096 V. When the internal reference is disabled

and the buffer is enabled, REF produces a buffered version of the voltage present on the REFIN pin

(VDD – 0.5 V maximum) useful when using low cost, low power references.

For improved drift performance, connect a precision reference to REF (0.5 V to VDD).

For any reference method, this pin needs decoupling with an external 10 μF capacitor connected as

close to REF as possible. See the Reference Decoupling section.

3

REFIN

AI/O

Internal Reference Output/Reference Buffer Input. See the Voltage Reference Output/Input section.

When using the internal reference, the internal unbuffered reference voltage is present and needs

decoupling with a 0.1 μF capacitor.

When using the internal reference buffer, apply a source between 0.5 V and 4.096 V that is buffered to

the REF pin as previously described.

4, 5

GND

P

Power Supply Ground.

6 to 9

IN4 to IN7

AI

Analog Input Channel 4, Analog Input Channel 5, Analog Input Channel 6, and Analog Input Channel 7.

10

COM

AI

Common Channel Input. All input channels, IN[7:0], can be referenced to a common-mode point of 0 V

or VREF/2 V.

11

CNV

DI

Conversion Input. On the rising edge, CNV initiates the conversion. During conversion, if CNV is held

high, the busy indictor is enabled.

12

DIN

DI

Data Input. This input is used for writing to the 14-bit configuration register. The configuration register

can be written to during and after conversion.

13

SCK

DI

Serial Data Clock Input. This input is used to clock out the data on SDO and clock in data on DIN in an

MSB first fashion.

14

SDO

DO

Serial Data Output. The conversion result is output on this pin and synchronized to SCK. In unipolar

modes, conversion results are straight binary; in bipolar modes, conversion results are twos

complement.

15

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).

16 to 19

IN0 to IN3

AI

Analog Input Channel 0, Analog Input Channel 1, Analog Input Channel 2, and Analog Input Channel 3.

21 (EPAD)

Exposed

Paddle

(EPAD)

The exposed paddle is not connected internally. For increased reliability of the solder joints, it is

recommended that the pad be soldered to the GND plane.

1

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