The AD7172-4 is a low noise, low power, multiplexed, Σ-Δ analog-to-digital converter (ADC) with 4- or 8-channel (fully differential/single-ended) inputs for low bandwidth signals. The AD7172-4 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 AD7172-4 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 reference inputs provide easy to drive high impedance inputs.
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 configurable on a per channel basis. General-purpose input/outputs (GPIOs) control external multiplexers synchronous to the ADC conversion timing. The specified temperature range is −40°C to +105°C.
The AD7172-4 is in a 5 mm × 5 mm, 32-lead LFCSP.
Note that, throughout this data sheet, the dual function pin names are referenced by the relevant function only.
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
4 fully differential channels or 8 single-ended channels
Crosspoint multiplexer
True rail-to-rail analog and reference input buffers
Internal or external clock
Power supply
AVDD1 = 3.0 V to 5.5 V, AVDD2 = IOVDD = 2 V to 5.5 V
Split supply with AVDD1 and AVSS at ±2.5 V or ±1.65 V
ADC current: 1.5 mA
Temperature range: −40°C to +105°C
3- or 4-wire serial digital interface (Schmitt trigger on SCLK)
Serial port interface (SPI), QSPI-, MICROWIRE-, and DSPcompatible
