The AD7175-2 is a low noise, fast settling, multiplexed, 2-/4- channel (fully/pseudo differential) Σ-Δ analog-to-digital converter (ADC) for low bandwidth inputs. It has a maximum channel scan rate of 50 kSPS (20 µs) for fully settled data. The output data rates range from 5 SPS to 250 kSPS.
The AD7175-2 integrates key analog and digital signal conditioning blocks to allow users to configure an individual setup for each analog input channel in use. Each feature can be user selected on a per channel basis. 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 output reference buffer) adds embedded functionality to reduce external component count.
The digital filter allows simultaneous 50 Hz/60 Hz rejection at 27.27 SPS output data rate. The user can switch between different filter options according to the demands of each channel in the application. The ADC automatically switches through each selected channel. Further digital processing functions include offset and gain calibration registers, configurable on a per channel basis.
The device operates with a 5 V AVDD1, or ±2.5 V AVDD1/AVSS, and 2 V to 5 V AVDD2 and IOVDD supplies. The specified operating temperature range is −40°C to +105°C. The AD7175-2 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: 5 SPS to 250 kSPS
Channel scan data rate of 50 kSPS/channel (20 µs settling)
Performance specifications
17.2 noise free bits at 250 kSPS
20 noise free bits at 2.5 kSPS
24 noise free bits at 20 SPS
INL: ±1 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
Internal or external clock
Power supply: AVDD1 = 5 V, AVDD2 = IOVDD = 2 V to 5 V
Split supply with AVDD1/AVSS at ±2.5 V
ADC current: 8.4 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 DSP compatible
