A 24-28GHz Gm-Boosted High Linearity CMOS LNA for 5G NR Applications

This paper presents a low-noise amplifier (LNA) designed for the front end of a 5G NR receiver, which features high linearity, low noise figure, and broad bandwidth. The LNA consists of a differential gm-boosted common-gate (CG) stage and a differential common-source (CS) stage. A novel three-coil transformer is used at the input end to convert a single-ended input to a differential signal while achieving broadband input matching and gm-boosting. In the second common-source stage, the transistor operates in the subthreshold region to mitigate the gain compression effect of the first stage to improve linearity. A transformer is used at the output end to convert the differential signal into a single-ended output.This LNA is implemented in the 40nm CMOS process, operating within the 24 to 28 GHz frequency range. It achieves a gain of 15.8 ± 0.6 dB across the entire bandwidth and exhibits good linearity, with an input 1-dB compression point (IP1dB) of -4.9 dBm. Throughout the bandwidth, the input return loss (S11) is less than -15 dB, and the output return loss (S22) is less than -10 dB. The LNA achieves a noise figure ranging from 4.1 to 4.3 dB across the bandwidth.