AD7734

Data Sheet

Rev. A | Page 2 of 32

Table of Contents

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

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

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

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

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

AD7734—Specifications.................................................................. 3

Timing Specifications....................................................................... 6

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

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

Output Noise and Resolution Specification................................ 10

Chopping Enabled...................................................................... 10

Chopping Disabled..................................................................... 11

Pin Configurations and Functional Descriptions ...................... 12

Register Description....................................................................... 14

Register Access............................................................................ 15

Communications Register......................................................... 15

I/O Port Register......................................................................... 16

Revision Register ........................................................................ 16

Test Register ................................................................................ 16

ADC Status Register................................................................... 17

Checksum Register..................................................................... 17

ADC Zero-Scale Calibration Register ..................................... 17

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

Channel Data Registers.............................................................. 17

Channel Zero-Scale Calibration Registers.............................. 18

Channel Full-Scale Calibration Registers................................ 18

Channel Status Registers ........................................................... 18

Channel Setup Registers............................................................ 19

Channel Conversion Time Registers ....................................... 19

Mode Register............................................................................. 20

Digital Interface Description ........................................................ 22

Hardware ..................................................................................... 22

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

Access the AD7734 Registers.................................................... 23

Single Conversion and Reading Data...................................... 23

Dump Mode................................................................................ 24

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

Continuous Read (Continuous Conversion) Mode .............. 25

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

Analog Front End....................................................................... 26

Analog Input’s Extended Voltage Range ................................. 27

Chopping..................................................................................... 27

Multiplexer, Conversion, and Data Output Timing .............. 28

Sigma-Delta ADC ...................................................................... 28

Frequency Response .................................................................. 29

Voltage Reference Inputs........................................................... 29

Reference Detect......................................................................... 29

I/O Port........................................................................................ 30

Calibration................................................................................... 30

ADC Zero-Scale Self-Calibration ............................................ 30

Per Channel System Calibration .............................................. 30

Outline Dimensions....................................................................... 32

REVISION HISTORY

7/12—Rev. 0 to Rev. A

Changes to ADC Performance Chop Enabled Parameter .......... 3

Changes to Figure 22...................................................................... 25

2/03—Revision 0: Initial Version