GENERAL DESCRIPTION

The AD7781 is a complete, low power front-end solution for bridge sensor products, including weigh scales, strain gages, and pressure sensors. It contains a precision, low power, 20-bit sigma-delta (Σ-Δ) ADC, an on-chip, low noise programmable gain amplifier (PGA), and an on-chip oscillator.

FEATURES

Pin-programmable filter response

Update rate: 10 Hz or 16.7 Hz

Pin-programmable in-amp gain

Pin-programmable power-down and reset

Status function

Internal clock oscillator

Internal bridge power-down switch

Current

115 μA typical (gain = 1)

330 μA typical (gain = 128)

Simultaneous 50 Hz/60 Hz rejection

Power supply: 2.7 V to 5.25 V

−40°C to +105°C temperature range

Independent interface power supply

Packages

14-lead, narrow body SOIC

16-lead TSSOP

2-wire serial interface (read-only device)

SPI compatible

Schmitt trigger on SCLK

APPLICATIONS

Weigh scales

Pressure measurement

Industrial process control

Portable instrumentation