GENERAL DESCRIPTION

The AD7719 is a complete analog front end for low frequency measurement applications. It contains two high resolution Σ-∆ ADCs, switchable matched excitation current sources, low-side power switches, digital I/O port, and temperature sensor.

FEATURES

HIGH RESOLUTION Σ-Δ ADCs

2 Independent ADCs (16- and 24-Bit Resolution)

Factory-Calibrated (Field Calibration Not Required)

Output Settles in 1 Conversion Cycle (Single

Conversion Mode)

Programmable Gain Front End

Simultaneous Sampling and Conversion of 2

Signal Sources

Separate Reference Inputs for Each Channel

Simultaneous 50 Hz and 60 Hz Rejection at 20 Hz

Update Rate

ISOURCE Select™

24-Bit No Missing Codes—Main ADC

13-Bit p-p Resolution @ 20 Hz, 20 mV Range

18-Bit p-p Resolution @ 20 Hz, 2.56 V Range

INTERFACE

3-Wire Serial

SPI®, QSPI™, MICROWIRE™, and DSP Compatible

Schmitt Trigger on SCLK

POWER

Specified for Single 3 V and 5 V Operation

Normal: 1.5 mA Typ @ 3 V

Power-Down: 10 μA (32 kHz Crystal Running)

ON-CHIP FUNCTIONS

Rail-Rail Input Buffer and PGA

4-Bit Digital I/O Port

On-Chip Temperature Sensor

Dual Switchable Excitation Current Sources

Low-Side Power Switches

Reference Detect Circuit

APPLICATIONS

Sensor Measurement

Temperature Measurement

Pressure Measurement

Weigh Scales

Portable Instrumentation

4 to 20 mA Transmitters