4 and 8 channel 16-bit ADCs for precision signal acquisition from Texas Instruments

The ADS1174 and ADS1178 feature 25kHz bandwidth, 2uV/C offset drift and up to 97dB signal-to-noise ratio (SNR). Two operating modes allow for optimization of speed (52kSPS) or power dissipation (7mW/channel).

Traditionally, industrial delta-sigma ADCs offering good drift performance use digital filters with large passband droop, resulting in limited signal bandwidth and mostly suited for DC measurements. High-resolution ADCs for audio applications offer larger usable bandwidths, but the offset and drift specifications are significantly worse (and often unspecified) than their industrial counterparts. The ADS1174 and ADS1178 combine these two types of converters, allowing high-precision industrial measurements with excellent DC and AC specifications.

The high-order, chopper-stabilized modulator achieves very low drift and low noise over the signal bandwidth of DC up to the Nyquist frequency. The onboard decimation filter suppresses modulator and out-of-band noise, providing a usable signal bandwidth up to 90 percent of the Nyquist rate with stopband attenuation of 100dB.

A selectable SPI or frame sync serial interface allows for convenient interfacing to DSPs, FPGAs and microcontrollers. Either interface supports daisy chaining to simplify readback of multiple ADS1174 or ADS1178 ADCs in high channel-count systems. The ADCs are fully specified over the industrial temperature range of -40C to +105C. Available in identical packages, the ADCs are drop-in compatible with the high-performance, 24-bit ADS1274 and ADS1278 for convenient upgrades.