The ADS1246, ADS1247, and ADS1248 are highly-integrated, precision, 24-bit analog-to-digital converters (ADCs). The devices feature an onboard, low-noise, programmable gain amplifier (PGA), a precision delta-sigma (ΔΣ) ADC with a single-cycle settling digital filter, and an internal oscillator. The ADS1247 and ADS1248 also provide a built-in, very low drift voltage reference with 10-mA output capacity, and two matched programmable current digital-to-analog converters (DACs). The devices provide a complete front-end solution for temperature sensor applications including thermal couples, thermistors, and resistance temperature detectors (RTDs).
An input multiplexer supports four differential inputs for the ADS1248, two for the ADS1247, and one for the ADS1246. In addition, the multiplexer has a sensor burn-out detect, voltage bias for thermocouples, system monitoring, and general-purpose digital I/Os (ADS1247 and ADS1248). The onboard, low-noise PGA provides selectable gains of 1 to 128. The ΔΣ modulator and adjustable digital filter settle in only one cycle, for fast channel cycling when using the input multiplexer, and support data rates up to 2 kSPS. For data rates of 20 SPS or less, both 50-Hz and 60-Hz interference are rejected by the filter.
