Design theory and performance of 1-GHz CMOS downconversion and upconversion mixers

A CMOS mixer topology capable of both downconversion and upconversion mixin g for use in integrated wireless transceivers is presented. The mixing is b ased on two cross-coupled differential pairs as commutators with two source -followers as current modulators. Independence of the input and output band widths allows this topology to be optimized separately for either downconve rsion or upconversion mixer. The prototypes of both upconversion and downco nversion mixers, optimized for linearity and realized in 0.8 mu m CMOS tech nology, have been demonstrated to fully operate at 1 GHz with good linearit y and low power consumption. In addition, another mixer, optimized for nois e figure and realized in 0.5 mu m CMOS technology, has been designed to ach ieve a NF of around 12 dB.