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