GENERAL DESCRIPTION

The AD7715 is a complete analog front end for low frequency measurement applications. The part can accept low level input signals directly from a transducer and outputs a serial digital word. It employs a Σ-Δ conversion technique to realize up to 16 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog 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 output update rate.

FEATURES

Charge-balancing ADC

16-bits no missing codes

0.0015 nonlinearity

Programmable gain front end

Gains of 1, 2, 32 and 128

Differential input capability

Three-wire serial interface

SPI-, QSPI?-, MICROWIRE?-, and DSP-compatible

Ability to buffer the analog input

3 V (AD7715-3) or 5 V (AD7715-5) operation

Low supply current: 450 μA maximum @ 3 V supplies

Low-pass filter with programmable output update

16-lead SOIC/PDIP/TSSOP