AD7794

Preliminary Technical Data

REV.PrE 6/04 | Page 2

TABLE OF CONTENTS

AD7794—Specifications.................................................................. 3

Absolute Maximum Ratings.......................................................... 11

ESD Caution................................................................................ 11

Pin Configuration and Function Descriptions........................... 12

Typical Performance Characteristics ........................................... 14

On-chip Registers ........................................................................... 15

Communications Register (RS2, RS1, RS0 = 0, 0, 0) .............. 15

Status Register (RS2, RS1, RS0 = 0, 0, 0; Power-on/Reset =

0x88)............................................................................................. 16

Mode Register (RS2, RS1, RS0 = 0, 0, 1; Power-on/Reset =

0x000A)........................................................................................ 16

Configuration Register (rs2, RS1, RS0 = 0, 1, 0; Power-

on/Reset = 0x0710) .................................................................... 18

Data Register (RS2, RS1, RS0 = 0, 1, 1; Power-on/Reset =

0x000000) .................................................................................... 20

ID Register (RS2, RS1, RS0 = 1, 0, 0; Power-on/Reset = 0xxF)

....................................................................................................... 20

IO Register (RS2, RS1, RS0 = 1, 0, 1; Power-on/Reset = 0x00)

....................................................................................................... 20

OFFSET Register (RS2, RS1, RS0 = 1, 1, 0; Power-on/Reset =

0x800000) .................................................................................... 21

FULL-SCALE Register (RS2, RS1, RS0 = 1, 1, 1; Power-

on/Reset = 0x5xxxx5) ................................................................ 21

ADC Circuit Information.............................................................. 22

Overview ..................................................................................... 22

Noise Performance ..................................................................... 22

Digital Interface .......................................................................... 23

Single Conversion Mode ....................................................... 24

Continuous Conversion Mode............................................. 24

Continuous Read Mode ........................................................ 25

Circuit Description......................................................................... 26

Analog Input Channel ............................................................... 26

Bipolar/Unipolar Configuration .............................................. 26

Data Output Coding .................................................................. 26

Reference ..................................................................................... 26

Grounding and Layout .............................................................. 27

Outline Dimensions ....................................................................... 29

Ordering Guide .......................................................................... 29

REVISION HISTORY

REV.PrE, June 2004: Initial Version