High-speed SAR ADC data acquisition system has programmable, bipolar input ranges

The Texas Instruments ADS8691, ADS8695, and ADS8699 devices belong to a family of integrated data acquisition system based on a SAR ADC. The devices feature a high-speed, high-precision SAR ADC, integrated AFE input driver circuit, overvoltage protection circuit up to ±20V, and an on-chip 4.096V reference with extremely low temperature drift. The devices operate on a single 5V analog supply, but support true bipolar input ranges of ±12.288V, ±6.144V, ±10.24V, ±5.12V, and ±2.56V, as well as unipolar input ranges of 0V to 12.288V, 0V to 10.24V, 0V to 6.144V, and 0V to 5.12V. The gain and offset errors are accurately trimmed within the specified values for each input range to ensure high DC precision. The input range selection is done by software programming of the device internal registers. The devices offer a high resistive input impedance (=1mohm) irrespective of the selected input range. The multiSPI digital interface is backward-compatible to the traditional SPI protocol. Additionally, configurable features simplify interface to a wide range of host controllers.