Datasheet

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