AD7798/AD7799

Data Sheet

Rev. B | Page 2 of 28

TABLE OF CONTENTS

Features .............................................................................................. 1

Interface ............................................................................................. 1

Applications....................................................................................... 1

Functional Block Diagram .............................................................. 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Timing Characteristics..................................................................... 6

Absolute Maximum Ratings............................................................ 8

ESD Caution.................................................................................. 8

Pin Configuration and Function Descriptions............................. 9

Output Noise and Resolution Specifications .............................. 10

AD7798........................................................................................ 10

AD7799........................................................................................ 11

Typical Performance Characteristics ........................................... 12

On-Chip Registers.......................................................................... 13

Communication Register .......................................................... 13

Status Register............................................................................. 14

Mode Register ............................................................................. 14

Configuration Register .............................................................. 16

Data Register............................................................................... 17

ID Register................................................................................... 17

IO Register................................................................................... 17

Offset Register ............................................................................ 17

Full-Scale Register...................................................................... 17

ADC Circuit Information.............................................................. 18

Overview ..................................................................................... 18

Digital Interface.......................................................................... 19

Circuit Description......................................................................... 22

Analog Input Channel ............................................................... 22

Instrumentation Amplifier........................................................ 22

Bipolar/Unipolar Configuration .............................................. 22

Data Output Coding .................................................................. 23

Burnout Currents ....................................................................... 23

Reference ..................................................................................... 23

Reference Detect......................................................................... 23

Reset............................................................................................. 23

AVDD Monitor ............................................................................. 24

Calibration................................................................................... 24

Grounding and Layout .............................................................. 25

Applications Information .............................................................. 26

Weigh Scales................................................................................ 26

Outline Dimensions....................................................................... 27

Ordering Guide .......................................................................... 27

REVISION HISTORY

7/13—Rev. A to Rev. B

Changes to Table 3............................................................................ 8

Changes to Digital Interface Section............................................ 19

Changes to Ordering Guide .......................................................... 27

3/07—Rev. 0 to Rev. A

Updated Format..................................................................Universal

Changes to Specifications................................................................ 3

Changes to Table 5 and Table 6..................................................... 10

Changes to Table 7 and Table 8..................................................... 11

Changes to Table 14........................................................................ 15

Changes to Ordering Guide .......................................................... 27

1/05—Revision 0: Initial Version