Fully differential CMOS sigma-delta modulator for high performance analog-to-digital conversion with 5 V operating voltage

Abstract

The authors present a high-performance second-order sigma-delta modulator for modem and ISDN (integrated-services digital network) analog-to-digital (A/D) conversion applications. The major performance design limiting factors are demonstrated. It is shown that a true 16-bit A/D converter with single 5-V power supply for voice band can be realized with an oversampling ratio of 512; and a 16-bit dynamic range is achieved with an oversampling ratio of 256. The die size of the proposed modulator, using 2.5- mu m CMOS technology, is only 0.56 mm/sup 2/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>