A multi-mode continuously-tunable lowpass filter for zero-IF mobile applications

Abstract

This paper presents a tunable 50 kHz-2 MHz 3/sup rd/-order lowpass Butterworth Gm-C filter for use in a baseband module of a zero-IF cellular multistandard receiver, including GSM/DCS/PCS and W-CDMA, designed and fabricated in a 0.25 /spl mu/m, 2.5 V SiGe BiCMOS process. Measurements exhibit good inband linearity (up to +18 dBVp), large tuning range (>30:1), moderate noise and power consumption (1 mW to 4 mW per channel) for a silicon area of only 0.5 mm/sup 2/ (I&Q channels).