GENERAL DESCRIPTION

The AD7712 is a complete analog front end for low frequency measurement applications. The device has two analog input channels and accepts either low level signals directly from a transducer or high level (±4
VREF) signals, and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 24 bits of no missing codes performance. The low level input signal is applied to a proprietary programmable gain front end based around an analog modulator. The high level analog input is attenuated before being applied to the same modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register, allowing adjustment of the filter cutoff and settling time.

FEATURES

Charge Balancing ADC

24 Bits No Missing Codes

±0.0015 Nonlinearity

High Level and Low Level Analog Input Channels

Programmable Gain for Both Inputs Gains from 1 to 128 Differential Input for Low Level Channel

Low-Pass Filter with Programmable Filter Cutoffs

Ability to Read/Write Calibration Coefficients

Bidirectional Microcontroller Serial Interface

Internal/External Reference Option

Single- or Dual-Supply Operation

Low Power (25 mW typ) with Power-Down Mode (100 μW typ)

APPLICATIONS

Process Control

Smart Transmitters

Portable Industrial Instruments