Datasheet

AD7985

Rev. A | Page 2 of 28

TABLE OF CONTENTS

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

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

Application Diagram ........................................................................ 1

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

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

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

Timing Specifications .................................................................. 5

Absolute Maximum Ratings ............................................................ 6

ESD Caution .................................................................................. 6

Pin Configuration and Function Descriptions ............................. 7

Typical Performance Characteristics ............................................. 9

Terminology .................................................................................... 12

Theory of Operation ...................................................................... 13

Circuit Information .................................................................... 13

Converter Operation .................................................................. 13

Conversion Modes of Operation .............................................. 13

Typical Connection Diagram.................................................... 14

Analog Inputs.............................................................................. 15

Driver Amplifier Choice ........................................................... 15

Voltage Reference Input ............................................................ 16

Power Supply ............................................................................... 16

Digital Interface .............................................................................. 17

Data Reading Options ............................................................... 18

Mode, 3-Wire Without Busy Indicator ............................. 19

Mode, 3-Wire with Busy Indicator .................................... 20

Mode, 4-Wire Without Busy Indicator ............................. 21

Mode, 4-Wire with Busy Indicator .................................... 22

Chain Mode Without Busy Indicator ...................................... 23

Chain Mode with Busy Indicator ............................................. 24

Applications Information .............................................................. 25

Layout .......................................................................................... 25

Evaluating AD7985 Performance ............................................. 25

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

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

REVISION HISTORY

8/10—Rev. 0 to Rev. A

Change to Table 4, Conversion Time: CNV Rising Edge

to Data Available ............................................................................... 5

9/09—Revision 0: Initial Version