TThe AD7172-2 is an intelligent, low noise, low power, multiplexed, Σ-Δ analog-to-digital converter (ADC) with 2- or 4-channel (fully differential/single-ended) inputs for low bandwidth signals. The AD7172-2 has a maximum channel scan rate of 6.21 kSPS (161 µs) for fully settled data. The output data rates range from 1.25 SPS to 31.25 kSPS.
The AD7172-2 integrates key analog and digital signal conditioning blocks to allow users to configure an individual setup for each analog input channel in use via the SPI. Integrated true rail-to-rail buffers on the analog inputs and external reference inputs provide easy to drive high impedance inputs. The precision 2.5 V low drift (2 ppm/°C) band gap internal reference (with an output reference buffer) adds embedded functionality to reduce the external component count.
The digital filter allows simultaneous 50 Hz and 60 Hz rejection at a 27.27 SPS output data rate. The user can switch between different filter options according to the demands of each channel in the application, with further digital processing functions such as offset and gain calibration registers, which are also configurable on a per channel basis. General-purpose inputs/outputs (GPIOs) control external multiplexers synchronous to the ADC conversion timing.
The specified operating temperature range is −40°C to +105°C. The AD7172-2 is in a 24-lead TSSOP package.
Applications
Process control: PLC/DCS modules
\- Temperature and pressure measurement
Medical and scientific multichannel instrumentation
Chromatography
### Features and Benefits
Fast and flexible output rate: 1.25 SPS to 31.25 kSPS
Channel scan data rate of 6.21 kSPS/channel (161 µs settling)
Performance specifications
17.2 noise free bits at 31.25 kSPS
24 noise free bits at 5 SPS
INL: ±2 ppm of FSR
85 dB rejection of 50 Hz and 60 Hz with 50 ms settling
User configurable input channels
2 fully differential channels or 4 single-ended channels
Crosspoint multiplexer
On-chip 2.5 V reference (±2 ppm/°C drift)
True rail-to-rail analog and reference input buffers
