A 5 GHz 7.2 dB NF low power direct conversion receiver front-end with balun LNA

Abstract

A 5GHz low power direct conversion receiver radio frequency front-end with balun LNA is presented. A hybrid common gate and common source structure balun LNA is adopted, and the capacitive cross-coupling technique is used to reduce the noise contribution of the common source transistor. To obtain low 1/f noise and high linearity, a current mode passive mixer is preferred and realized. A current mode switching scheme can switch between high and low gain modes, and meanwhile it can not only perform good linearity but save power consumption at low gain mode. The front-end chip is manufactured on a 0.13-μm CMOS process and occupies an active chip area of 1.2 mm2. It achieves 35 dB conversion gain across 4.9–5.1 GHz, a noise figure of 7.2 dB and an IIP3 of −16.8 dBm, while consuming 28.4 mA from a 1.2 V power supply at high gain mode. Its conversion gain is 13 dB with an IIP3 of 5.2 dBm and consumes 21.5 mA at low gain mode.