A 5.6-GHz CMOS doubly balanced sub-harmonic mixer for direct conversion - Zero IF receiver

A New Low Power 5.6 GHz Doubly Balanced Sub-Harmonic Mixer for Industrial Scientific Medical (ISM) Band Direct Conversion - Zero IF Receiver in 0.25-mum CMOS is presented. The mixer uses a power efficient LO frequency generation scheme to overcome LO self-mixing problem common in conventional Direct Conversion Receivers (DCR). Simulated with 1% gm mismatch, 0.5% load mismatch and 2degrees LO phase error the mixer is able to achieve 55 dBm of IIP2, -6.5 dBm of IIP3 and voltage conversion gain of 8 dB while consuming less than 1.75 mA from a single 3V supply. The mixer also achieves input compression of -12 dBm and an overall double side band noise figure of 5.96 dB. The proposed mixer takes up less than 1mm(2) of silicon real estate.