A NOISE OPTIMIZED PASSIVE MIXER FOR CHARGE-DOMAIN SAMPLING APPLICATIONS

Abstract

This paper presents a circuit design technique, based on a CMOS charge-domain passive mixer, for WLAN applications in a 2.4 GHz band. The CMOS passive mixer is designed to mitigate the critical flicker noise problem that is frequently encountered in constitution of direct conversion receivers. The charge-domain method is employed to improve the high frequency performance and noise characteristic. The designed circuit is composed of a trans-conductance amplifier and a passive mixer with a capacitive charge storing load. Fabricated in 0.13 mu m CMOS process, this charge-domain mixer achieves a low flicker noise with corner frequency of under 100 kHz, 8.1 dB noise figure, 10.6 dB conversion voltage gain, 2.5 dBm IIP3, and -5.7 dBm P1dB with 2.4 GHz LO driving at 5 dBm. It consumes 4.31 mA from 1.5 V supply.