A Folded Cascode CMOS Low Noise Amplifier with Transformer Feedback

This study proposes a folded cascode CMOS low noise amplifier (LNA) with transformer feedback, implemented using a 0.13-μm CMOS process for wireless local area network front-end module applications. Compared to a conventional cascode inductive source degeneration LNA (ISDLNA), the folded cascode ISDLNA significantly improved the input-referred third-order intercept point (IIP3) as well as the 1-dB compression point (P1dB) by ensuring a large voltage headroom. Furthermore, the designed LNA also achieved a low noise figure (NF), while also saving the silicon area by magnetically coupling the source and folding inductors. When tested experimentally, the proposed LNA showed an S21 of 11.0 dB and an NF of 2.6 dB, while achieving an S11 of −7 dB at the operating frequency of 2.4 GHz. The measured input P1dB and IIP3 were −5.6 dBm and +2.5 dBm, respectively. The power dissipation was 9.6 mW from a 1.2-V supply voltage.