1

FEATURES

DESCRIPTION

APPLICATIONS

Input

Mux

DS ADC

REFP REFN

PGA

Gain=

1,2,64,or128

CAP

DVDD

DGND

AGND

A1/TEMP

(1)

A0

NOTE:(1)A1forADS1234,TEMPforADS1232.

AINP1

AINN1

AINP2

AINN2

AINP3

AINN3

AINP4

AINN4

ADS1234

Only

SCLK

SPEED

DRDY/DOUT

PDWN

GAIN[1:0]

AVDD

CAP

ExternalOscillator

InternalOscillator

CLKIN/XTAL1 XTAL2

ADS1232

ADS1234

SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008

www.ti.com

24-Bit Analog-to-Digital Converter

For Bridge Sensors

2

• Complete Front-End for Bridge Sensors

The ADS1232 and ADS1234 are precision 24-bit

analog-to-digital converters (ADCs). With an onboard,

• Up to 23.5 Effective Bits

low-noise

programmable

gain

amplifier

(PGA),

• Onboard, Low-Noise PGA

precision delta-sigma ADC and internal oscillator, the

• RMS Noise:

ADS1232/4 provide a complete front-end solution for

17nV at 10SPS (PGA = 128)

bridge sensor applications including weigh scales,

44nV at 80SPS (PGA = 128)

strain gauges and pressure sensors.

• 19.2-Bit Noise-Free Resolution at Gain = 64

The input multiplexer accepts either two (ADS1232)

• Over 100dB Simultaneous 50Hz and 60Hz

or four (ADS1234) differential inputs. The ADS1232

also includes an onboard temperature sensor to

Rejection

monitor ambient temperature. The onboard, low-noise

• Flexible Clocking:

PGA has a selectable gain of 1, 2, 64, or 128

Low-Drift Onboard Oscillator (±3%)

supporting a full-scale differential input of ±2.5V,

Optional External Crystal

±1.25V, ±39mV, or ±19.5mV. The delta-sigma ADC

• Selectable Gains of 1, 2, 64, and 128

has 23.5-bit effective resolution and is comprised of a

3rd-order modulator and 4th-order digital filter. Two

• Easy Ratiometric Measurements–

data rates are supported: 10SPS (with both 50Hz and

External Voltage Reference up to 5V

60Hz rejection) and 80SPS. The ADS1232/4 can be

• Selectable 10SPS or 80SPS Data Rates

clocked externally using an oscillator or a crystal.

• Two-Channel Differential Input with Built-In

There is also an internal oscillator available that

Temperature Sensor (ADS1232)

requires no external components. Offset calibration is

performed on-demand and the ADS1232/4 can be

• Four-Channel Differential Input (ADS1234)

put in a low-power standby mode or shut off

• Simple Serial Digital Interface

completely in power-down mode. All of the features of

• Supply Range: 2.7V to 5.3V

the

ADS1232/4

are

operated

through

simple

pin-driven control. There are no digital registers to

• –40°C to +105°C Temperature Range

program in order to simplify software development.

Data

are

output

over

an

easily-isolated

serial

interface that connects directly to the MSP430 and

• Weigh Scales

other microcontrollers.

• Strain Gauges

The ADS1232 is available in a TSSOP-24 package

• Pressure Sensors

and the ADS1234 is in a TSSOP-28. Both are fully

• Industrial Process Control

specified from -40

°C to +105°C.

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2005–2008, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.