24-bit converters

ADS1232 and ADS1234 are new 24-bit analog-to-digital converters (ADCs) from the company's Burr-Brown product line which integrate a low-noise programmable gain amplifier (PGA), precision delta-sigma ADC and internal oscillator.

Fabricated using TI's mixed-signal CMOS technology, the ADS1232 and ADS1234 provide a front-end solution for bridge sensor applications, including weigh scales, strain gauges and pressure sensors.

The input multiplexer accepts either two (ADS1232) or four (ADS1234) differential inputs. The ADS1232 includes an onboard temperature sensor to monitor ambient temperature. Following the multiplexer, the low-noise PGA features RMS noise of only 17nV (at 10SPS data rate) or 44nV (at 80SPS data rate) and has a selectable gain of 1, 2, 64 or 128, supporting a full-scale differential input of +/-2.5V, +/-1.25V, +/-39mV or +/-19.5mV. The PGA drives the high-resolution, delta-sigma ADC with 23.5 bits of RMS noise performance.

Dedicated I/O pins for setting gain, data rate and input channel (no on-chip digital registers to program) simplify control. Either the internal, low-drift oscillator, external crystal or external oscillator can provide the clocking. Data is output over an easily-isolated, two-wire interface that connects directly to TI's MSP430 and other microcontrollers. When not in use, the ADS1232 and ADS1234 can be put in a low-power standby mode, or shut down completely.

The ADS1232 and ADS1234, which are RoHS-compatible "Green" devices, are available now from TI and its authorised distributors.

The ADS1232 is packaged in a TSSOP-24 and is priced from $3.90 in 1,000 piece quantities. The ADS1234 is packaged in a TSSOP-28 and is priced from $4.50 in 1,000 piece quantities. Evaluation modules are also available.