User

's Guide

SBAU175A

– July 2010 – Revised August 2011

ADS1131REF and ADS1231REF

The ADS1131REF and the ADS1231REF are reference designs for delta-sigma analog-to-digital

converters (ADCs). The ADS1131REF contains the ADS1131 18-bit device, while the ADS1231REF

contains the ADS1231 24-bit device. Both systems contain all the circuitry and user interface elements

needed for a weigh-scale digitizer, and are meant as examples of a good design for a basic weigh-scale

system. Each system is also suitable for general evaluation of the respectively installed ADC. Throughout

this document, the term ADS1x31REF is used to refer to the common features and functions for both

systems.

The ADS1x31REF hardware has the following features:

•

ADS1131 ADC for the ADS1131REF and ADS1231 ADC for the ADS1231REF

•

Connections for load cells or other voltage sources

•

Low-side excitation switch on the load cell header connector

•

Ample EMI/RFI suppression between the ADC and rest of design

•

Eight-digit starburst LCD readout

•

USB connection for firmware updates and remote control

•

Designed for very low power consumption

•

Battery (9V) or wall power

Version 1.0.0 of the firmware includes the following features:

•

Weigh-scale mode with two-point calibration

•

Complete configuration of the device

•

Real-time peak-to-peak and RMS noise calculation

•

Autoranging voltage display

•

Noise displayed in volts, codes, and bits

•

Voltage displayed in volts or codes

•

Adjustable averaging mode

•

Raw hexadecimal code display

•

Simple and fast configuration

•

Parameters saved to internal flash memory

•

Computer link

Graphical PC software is also provided for histogram display, datalogging, and device control.

We welcome bug reports and suggestions for additional features; please contact the Texas Instruments

Precision Analog Applications Group.

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All other trademarks are the property of their respective owners.

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SBAU175A

– July 2010 – Revised August 2011

ADS1131REF and ADS1231REF

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