DIN 4-Channel, 10 V Input Range, High Throughput, 24-Bit Sigma-Delta ADC Data Sheet AD7734 FEATURES FUNCTIONAL BLOCK DIAGRAM REFIN() REFIN(+) High resolution analog-to-digital converter (ADC) 24 bits no missing codes AIN0 REFERENCE DETECT 0.0025% nonlinearity Optimized for fast channel switching AIN1 BUFFER 18-bit p-p resolution (21 bits effective) at 500 Hz MUX 16-bit p-p resolution (19 bits effective) at 2 kHz 24-BIT AIN2 - ADC 14-bit p-p resolution (18 bits effective) at 15 kHz On-chip per channel system calibration AIN3 4 single-ended analog inputs AD7734 Input ranges +5 V, 5 V, +10 V, 10 V BIASHI Overvoltage tolerant BIASLO SCLK Up to 16.5 V not affecting adjacent channel DOUT CALIBRATION SERIAL Up to 50 V absolute maximum CIRCUITRY INTERFACE 3-wire serial interface CS SPI, QSPI, MICROWIRE, and DSP compatible Schmitt trigger on logic inputs P0 RDY CLOCK CONTROL Single-supply operation I/O PORT GENERATOR LOGIC RESET SYNC/P1 5 V analog supply 3 V or 5 V digital supply AGND AV MCLKOUT MCLKIN DGND DV DD DD Package: 28-lead TSSOP Figure 1. APPLICATIONS PLCs/DCS Multiplexing applications Process control Industrial instrumentation GENERAL DESCRIPTION The AD7734 is a high precision, high throughput analog front 3-wire operation and is compatible with microcontrollers and end. True 16-bit p-p resolution is achievable with a total conversion digital signal processors. All interface inputs are Schmitt triggered. time of 500 s (2 kHz channel switching), making it ideally suitable The device is specified for operation over the extended industrial for high resolution multiplexing applications. temperature range of 40C to +105C. The device can be configured via a simple digital interface, which Other devices in the AD7734 family are the AD7732 and the allows users to balance the noise performance against data AD7738. throughput up to 15.4 kHz. The AD7732 is similar to the AD7734, but its analog front end The analog front end features four single-ended input channels features two fully differential input channels. with unipolar or true bipolar input ranges to 10 V while operating The AD7738 analog front end is configurable for four fully from a single +5 V analog supply. The device has an overrange differential or eight single-ended input channels, features and underrange detection capability and accepts an analog 0.625 V to 2.5 V bipolar/unipolar input ranges, and accepts a input overvoltage to 16.5 V without degrading the common-mode input voltage from 200 mV to AVDD 300 mV. performance of the adjacent channels. The AD7738 multiplexer output is pinned out externally, allowing The differential reference input features No-Reference detect the user to implement programmable gain or signal conditioning capability. The ADC also supports per channel system calibra- before being applied to the ADC. tion options. The digital serial interface can be configured for Rev. B Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20032015 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 03071-001AD7734 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Channel Setup Registers ............................................................ 19 Applications ....................................................................................... 1 Channel Conversion Time Registers ....................................... 19 Functional Block Diagram .............................................................. 1 Mode Register ............................................................................. 20 General Description ......................................................................... 1 Digital Interface Description ........................................................ 22 Revision History ............................................................................... 2 Hardware ..................................................................................... 22 Specif icat ions ..................................................................................... 3 Reset ............................................................................................. 23 Timing Specifications .................................................................. 6 Access the AD7734 Registers .................................................... 23 Absolute Maximum Ratings ............................................................ 8 Single Conversion and Reading Data ...................................... 23 ESD Caution .................................................................................. 8 Dump Mode ................................................................................ 24 Typical Performance Characteristics ............................................. 9 Continuous Conversion Mode ................................................. 24 Output Noise and Resolution Specification ................................ 10 Continuous Read (Continuous Conversion) Mode ............. 25 Chopping Enabled ...................................................................... 10 Circuit Description......................................................................... 26 Chopping Disabled ..................................................................... 11 Analog Front End ....................................................................... 26 Pin Configuration and Function Descriptions ........................... 12 Analog Inputs Extended Voltage Range ................................. 27 Register Description ....................................................................... 14 Chopping ..................................................................................... 27 Register Access ............................................................................ 15 Multiplexer, Conversion, and Data Output Timing .............. 28 Communications Register ......................................................... 15 - ADC ..................................................................................... 28 I/O Port Register ......................................................................... 16 Frequency Response .................................................................. 29 Revision Register ........................................................................ 16 Voltage Reference Inputs ........................................................... 29 Test Register ................................................................................ 16 Reference Detect ......................................................................... 29 ADC Status Register ................................................................... 16 I/O Port ........................................................................................ 30 Checksum Register ..................................................................... 17 C a l ibr at ion ................................................................................... 30 ADC Zero-Scale Calibration Register ..................................... 17 ADC Zero-Scale Self-Calibration ............................................ 30 ADC Full-Scale Register ............................................................ 17 Per Channel System Calibration .............................................. 30 Channel Data Registers.............................................................. 17 Outline Dimensions ....................................................................... 32 Channel Zero-Scale Calibration Registers .............................. 18 Ordering Guide .......................................................................... 32 Channel Full-Scale Calibration Registers ................................ 18 Channel Status Registers ........................................................... 18 REVISION HISTORY 9/15Rev. A to Rev. B Change to Figure 14 ....................................................................... 22 Changes to Figure 28 ...................................................................... 29 Changes to Ordering Guide .......................................................... 32 7/12Rev. 0 to Rev. A Changes to ADC Performance Chop Enabled Parameter .......... 3 Changes to Figure 22 ...................................................................... 25 2/03Revision 0: Initial Version Rev. B Page 2 of 32
