Industrial ADCs Run Quietly

Claiming best-in-class noise and speed specs, the ADS1255 and ADS1256 industrial a/d converters exhibit noise-free resolutions up to 23 bits, data rates up to 30 ksamples/s, and a maximum non- linearity of ±0.001%. They also integrate a number of on-board peripherals, including an input multiplexer, input buffer, and a programmable gain amplifier (PGA). Both converters consist of a fourth-order, delta-sigma modulator followed by a programmable digital filter. The input multiplexer accommodates differential or single-ended signals and also verifies sensor integrity. The ADS1255 supports one differential or two single-ended inputs and has two general-purpose digital I/Os, while the ADS1256 supports four differential or eight single-ended inputs and has four general-purpose digital I/Os. Communication is via an SPI interface. The ADS1255 in an SSOP-20 and the ADS1256 in an SSOP-28 cost $7.95 and $8.95 each/1,000, respectively. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.