GENERAL DESCRIPTION

The AD7176-2 is a fast settling, highly accurate, high resolution, multiplexed Σ-Δ analog-to-digital converter (ADC) for low bandwidth input signals. Its inputs can be configured as two fully differential or four pseudo differential inputs via the integrated crosspoint multiplexer. An integrated precision, 2.5 V, low drift (2 ppm/°C), band gap internal reference (with an output reference buffer) adds functionality and reduces the external component count.

FEATURES

Fast and flexible output rate—5 SPS to 250 kSPS

Fast settling time—20 µs

Channel scan data rate of 50 kSPS/channel

Performance specifications

17 noise free bits at 250 kSPS

20 noise free bits at 2.5 kSPS

22 noise free bits at 5 SPS

INL ±2.5 ppm of FSR

85 dB rejection of 50 Hz and 60 Hz with 50 ms settling

User-configurable input channels

2 fully differential or 4 pseudo differential

Crosspoint multiplexer

On-chip 2.5 V reference (drift 2 ppm/°C)

Internal oscillator, external crystal, or external clock

Power supply

Single supply: 5 V AVDD1, 2 V to 5 V AVDD2 and IOVDD

Optional split supply: AVDD1 and AVSS ± 2.5 V

Current: 7.8 mA

Temperature range: −40°C to +105°C

3- or 4-wire serial digital interface (Schmitt trigger on SCLK)

CRC error checking

SPI, QSPI, MICROWIRE, and DSP compatible

APPLICATIONS

Process control: PLC/DCS modules

Temperature and pressure measurement

Medical and scientific multichannel instrumentation

Chromatography