ADS7882

PIN FUNCTIONS (continued)

PIN

I/O

DESCRIPTION

NAME

NO. PFB

8-BIT BUS

16-BIT BUS

DATA BUS

BYTE = 0

BYTE = 1

BYTE = 0

PWD/RST

38

I

Active low input, acts as device power down/device reset signal.

Byte select input. Used for 8-bit bus reading.

BYTE

39

I

0: No fold back

1: Lower byte D[3:0] is folded back to high byte so D3 is available in D11 place.

STATUS OUTPUT

BUSY

36

O

Status output. High when a conversion is in progress.

POWER SUPPLY

+VBD

24, 34

–

Digital power supply for all digital inputs and outputs. Refer to Table 3 for layout guidelines.

BDGND

25, 35

–

Digital ground for all digital inputs and outputs. Short to analog ground plane below the device.

4, 9, 10, 13,

+VA

–

Analog power supplies. Refer to Table 3 for layout guidelines.

43, 46

5, 8, 11, 12,

AGND

–

Analog ground pins. Short to analog ground plane below the device.

14, 15, 44, 45

ANALOG INPUT

+IN

6

I

Noninverting analog input channel

–IN

7

I

Inverting analog input channel

Reference (positive) input. Needs to be decoupled with REFM pin using 0.1-

µF bypass capacitor

REFIN

1

I

and 1-

µF storage capacitor.

Internal reference output. To be shorted to REFIN pin when internal reference is used. Do not

REFOUT

2

O

connect to REFIN pin when external reference is used. Always needs to be decoupled with

AGND using 0.1-

µF bypass capacitor.

REFM

47, 48

I

Reference ground. Connect to analog ground plane.

NC

–

No connection

Copyright © 2008, Texas Instruments Incorporated

Submit Documentation Feedback

7

Product Folder Link(s): ADS7882