AD7997/AD7998

Rev. 0 | Page 2 of 32

TABLE OF CONTENTS

AD7997 Specifications..................................................................... 3

AD7998 Specifications..................................................................... 5

I2C Timing Specifications ................................................................ 7

Absolute Maximum Ratings............................................................ 9

ESD Caution.................................................................................. 9

Pin Configuration and Pin Function Descriptions.................... 10

Terminology .................................................................................... 11

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

Circuit Information ........................................................................ 15

Converter Operation.................................................................. 15

Typical Connection Diagram ................................................... 16

Analog Input ............................................................................... 16

Internal Register Structure ............................................................ 18

Address Pointer Register ........................................................... 18

Configuration Register .............................................................. 19

Conversion Result Register ....................................................... 20

Limit Registers ............................................................................ 20

Alert Status Register (CH1 to CH4) ........................................ 21

Cycle Timer Register.................................................................. 22

Sample Delay and Bit Trial Delay............................................. 22

Serial Interface ................................................................................ 23

Serial Bus Address ...................................................................... 23

Writing to the AD7997/AD7998 .................................................. 24

Writing to the Address Pointer Register for a Subsequent

Read.............................................................................................. 24

Writing a Single Byte of Data to the Alert Status Register or

Cycle Register.............................................................................. 24

Writing Two Bytes of Data to a Limit, Hysteresis, or

Configuration Register .............................................................. 24

Reading Data from the AD7997/AD7998................................... 26

ALERT/BUSY Pin .......................................................................... 27

SMBus ALERT ............................................................................ 27

BUSY ............................................................................................ 27

Placing the AD7997-1/AD7998-1 into High Speed Mode ... 27

The Address Select (AS) Pin ..................................................... 27

Modes of Operation ....................................................................... 28

Mode 1—Using the CONVST Pin ........................................... 28

Mode 2 – COMMAND MODE ............................................... 29

Mode 3—Automatic Cycle Interval Mode.............................. 30

Outline Dimensions ....................................................................... 31

Ordering Guide .......................................................................... 31

Related Parts in I2C-Compatible ADC Product Family........ 31

REVISION HISTORY

9/04—Revision 0: Initial Version