GENERAL DESCRIPTION
The AD7191 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (Σ-Δ) ADC. The on-chip low noise gain stage means that signals of small amplitude can be interfaced directly to the ADC. It contains two differential analog inputs. The part also includes a temperature sensor that can be used for temperature compensation.

FEATURES
Pin-programmable output rate
Output data rate: 10 Hz, 50 Hz, 60 Hz, 120 Hz
Pin-programmable PGA
Gain: 1, 8, 64, 128
Pin-programmable power-down and reset
RMS noise: 15 nV @ 10 Hz (gain = 128)
Up to 21.5 noise free bits (gain = 1)
Internal or external clock
Bridge power-down switch
Offset drift: 5 nV/°C
Gain drift: 1 ppm/°C
Specified drift over time
Simultaneous 50 Hz/60 Hz rejection
Internal temperature sensor
Power supply: 3 V to 5.25 V
Current: 4.35 mA
Temperature range: –40°C to +105°C
Package: 24-lead TSSOP

INTERFACE
2-wire serial
SPI, QSPI™, and MICROWIRE™ compatible
Schmitt trigger on SCLK

APPLICATIONS
Weigh scales
Strain gauge transducers
Pressure measurement
Medical and scientific instrumentation