How delta-sigma ADCs work, Part 1

Texas Instruments

Published Date: 09/16/2011

Description

Analog techniques have dominated signal processing for years, but digital techniques are slowly encroaching into this domain. The design of delta-sigma (DS) analog-todigital converters (ADCs) is approximately three-quarters digital and one-quarter analog. DS ADCs are now ideal for converting analog signals over a wide range of frequencies, from DC to several megahertz. Basically, these converters consist of an oversampling modulator followed by a digital/ decimation filter that together produce a high-resolution data-stream output.

This two-part article will look closely at the DS ADC’s core. Part 1 will explore the basic topology and function of the DS modulator, and Part 2 will explore the basic topology and function of the digital/decimation filter module.