A flicker noise/IM3 cancellation technique for active mixer using negative impedance

This paper presents an approach to simultaneouslycancel flicker noise and IM3 in Gilbert-type mixers, utilizing negative impedances. For proof of concept, two prototype double-balanced mixers in 0.16- m CMOS are fabricated. The first demonstration mixer chip was optimized for full IM3 cancellationand partial flicker noise cancellation; this chip achieves 9-dB flicker noise suppression, improvements of 10 dB for IIP3, 5 dB for conversion gain, and 1 dB for input P1 dB while the thermal noise increased by 0.1 dB. The negative impedance increases the powerconsumption for the mixer by 16% and increases the die area by 8% (46 28 m ). A second demonstration mixer chip aims atfull flicker noise cancellation and partial IM3 cancellation, while operating on a low supply voltage ( 0.67 x Vdd; in this chip,the negative impedance increases the power consumption by 7.3% and increases the die area by 7% (50 20 m ). For one chip sample, measurements show 10-dB flicker noise suppression within 200% variation of the negative impedance bias current; for ten randomly selected chip samples, 11-dB flicker noisesuppression is measured.