A 28GHz, 7mW, 32dB gain and 3.3dB NF, G<inf>m</inf>-boosted CG-CS LNA for 5G RF beamformers

A low power, high gain 28GHz mm-wave two stage cascaded CG-CS LNA in a 45nm bulk CMOS process is reported for low power 5G RF beamformers. High gain in the LNA is essential in RF beamformers to compensate the loss from passive phase shifters unlike a hybrid beamformer. To achieve high gain, low NF and low power consumption, the first stage utilizes the concept of passive gm boosting in a CG cascoded stage coupled with series peaking. A regular CS cascoded 2ndstage boosts gain further. Post-layout EM simulations predict a gain of 32dB and a noise figure of 3.3dB at a power consumption of only 7mW. As a proof of concept, a traditional two stage cascoded CS LNA has also been implemented utilizing slow wave transmission lines to highlight a 3X increased power consumption with similar small signal gain and NF. An IC, package and PCB co-analysis methodology for such mmwave blocks is also introduced as it becomes essential to verify the chip in context of Package/PCB before tapeout.