A linearized common-gate low-noise amplifier using active cross-coupled feedback technique

Abstract

A wideband linearized common-gate low-noise amplifier (LNA) is proposed. The linearity is improved by active cross-coupled feedback technique. The active cross-coupled feedback circuit, consisting of a complementary source follower and a feedback capacitor, is employed to enhance loop gain, and acquire linearity improvement. A passive cross-coupled feedback removes the second-order harmonic feedback effect to the input-referred third-order intercept point (IIP3). An enhanced LC-match input network and forward isolation of the active cross-coupled feedback enable the proposed LNA with wideband input matching and flat gain performance, respectively. Fabricated in a 0.13 μm RF CMOS process, the LNA achieves a flat voltage gain of 14.5 dB, an NF of 2.5---3.4 dB, and an IIP3 of 3.1---4.3 dBm over a 3 dB bandwidth of 0.1---1.2 GHz. It consumes only 3.5 mA from a 1.2 V supply and occupies an area of 0.2 mm2.