A 2-V 900-MHz CMOS mixer for GSM receivers

A 2-V 900-MHz downconversion mixer to be used in a single-chip CMOS receiver is presented. The mixer is based on a Gilbert cell but uses two source-followers as current modulators rather than a common-source input stage in order to support low-voltage operation and to improve the linearity. Two prototypes have been made for different design trade-off. The first mixer prototype achieves a measured conversion gain of -8 dB and an IIP3 of 26 dBm with a power consumption of 1.5 mW from a 3-V supply. The second prototype has a measured conversion gain of -2 dB, a noise figure (NF) of 22 dB and an IIP3 of 6 dBm with a power consumption of 3 mW from a single 2-V supply.