A 1.2-V dual-mode WCDMA/GPRS ΣΔ modulator

Abstract

A dual-mode /spl Sigma//spl Delta/ modulator is designed to meet the specifications of a WCDMA/GPRS receiver and is composed of a single-bit second-order modulator followed by a multi-bit stage that adapts performance to broadband signals. The modulator achieves 82dB and 70dB of dynamic range over bandwidths of 100kHz and 1.92MHz, respectively, and dissipates 4.3mW from a 1.2V supply. The circuit is implemented in 0.13/spl mu/m CMOS technology and occupies an active area of 0.2mm/sup 2/.