A 140-Gbps 1-to-21-GHz Ultra-Wideband LNA Achieving 1.95-to-3-dB NF Using Gm-Assisted-Feedback Noise Suppression Technique in 40nm Bulk CMOS

This paper presents an ultra-wideband low-noise amplifier (LNA) with gm-assisted-feedback noise suppression technique for ultra-wideband RF front-end. Compared to the traditional resistive feedback wideband LNAs, the proposed LNA blocks the noise current from the feedback resistor with a simple additional gm-cell, thus achieving a lower overall NF. A source coupling transformer is also utilized to maintain a wideband flat gain. Fabricated in a 40-nm bulk CMOS process, the LNA prototype achieves a measured bandwidth of 1-to-21-GHz, NF of 1.95-to-3-dB, S21 of 20.6-to-22.4-dB, while consuming 21.6 mA from a 1.2 V power supply. It reports the lowest and the flattest NF among the recent-published bulk CMOS ultra-wideband LNAs, it also supports ultra-wideband modulation signal with a date rate of 140 Gbps.