Linearization of differential CMOS low noise amplifier using cross-coupled post distortion canceller

Abstract

A post-linearization technique for the differential CMOS LNA is presented. The proposed method uses an additional cross-coupled FET pair which generates the 3rd-order inter-modulation (IM3) current to cancel out the IM3 current of the differential amplifier while minimizing the degradation of noise figure and avoiding the gain reduction. This technique is applied to enhance the linearity of the differential CMOS LNA using 0.18-mum technology. The LNA achieved +10.2-dBm IIP3 with 13.7-dB gain and 1.68-dB NF at 2 GHz consuming 11.8-mA from a 1.8-V supply.