Four and eight-channel integrated data acquisition systems based 16-bit SAR ADCs

The ADS8684 and ADS8688 are 4- and 8-channel, integrated data acquisition systems based on a 16-bit successive approximation (SAR) analog-to-digital converter (ADC), operating at a throughput of 500 kSPS. The Texas Instruments (TI) devices feature integrated analog front-end circuitry for each input channel with overvoltage protection up to ±20 V, a 4- or 8-channel multiplexer with automatic and manual scanning modes, and an on-chip, 4.096V reference with low temperature drift. Operating on a single 5V analog supply, each input channel on the devices can support true bipolar input ranges of ±10.24V, ±5.12V, and ±2.56V, as well as unipolar input ranges of 0V to 10.24V and 0V to 5.12V. The gain of the analog front-end for all input ranges is accurately trimmed to ensure a high dc precision. The input range selection is software-programmable and independent for each channel. The devices offer a 1Mohm constant resistive input impedance irrespective of the selected input range, says the company.