A 1.8 mW CMOS ΣΔ modulator with integrated mixer for A/D conversion of IF signals

Abstract

This CMOS IF/spl Sigma//spl Delta/ modulator combines the functions of an IF mixer and an anti-aliasing filter with a continuous-time (CT) baseband /spl Sigma//spl Delta/ modulator for A/D conversion of IF signals in radio receivers. Advantage is taken of the high linearity and low-power of the CT baseband /spl Sigma//spl Delta/ modulator. The resulting IF/spl Sigma//spl Delta/ modulator consumes 1.8 mW and has +36 dBV IP3. The IF /spl Sigma//spl Delta/ modulator of this paper is for mobile phones (GSM specification), and is promising for application in other types of receivers.