An IP2 Improvement Technique for Zero-IF Down-Converters

An IP2 calibration circuit to improve the 2 nd -order nonlinearity of mixers in zero or low-IF receivers is presented. The circuit allows the mixers to be optimized independently, and has negligible impact on receiver noise figure, area, and power consumption. A prototype transceiver including the calibration circuitry in 0.13mum CMOS is fabricated. An average IIP2 improvement of 18dB is measured