An X-band high linearity rail-to-rail variable-gain LNA in 65 nm CMOS technology

Abstract

In this paper a low noise figure (NF) variable-gain low noise amplifier (VG-LNA) is presented. In the proposed circuit a gain cascaded branch is utilized to provide a rail-to-rail control voltage to vary the gain of LNA in a wide range and improve the dynamic range of the front-end receiver block. Besides, the gain of the proposed LNA is amplified by using a current reused technique with the rearrangement of its components, leading to an improvement of the total occupied area by more than 22%. The performance of the proposed VG-LNA is evaluated by the post-layout simulation results provided by TSMC 65 nm CMOS technology with a 1.2 V supply voltage. The simulation results demonstrate that the gain of the circuit is varied linearly from 15 to 24.2 dB by changing the control voltage from rail-to-rail. Besides, the proposed VG-LNA has an NF of less than 3.3 dB and S11 of better than − 23 dB in a wide temperature range while the power consumption is 9.3 mW @ 9.3 GHz center frequency. Also, the occupied area of the VG-LNA is 0.187 mm² (407 µm × 460 µm).