A 2.5GHz 32nm 0.35mm<sup>2</sup> 3.5dB NF −5dBm P<inf>1dB</inf> fully differential CMOS push-pull LNA with integrated 34dBm T/R switch and ESD protection

Abstract

In this paper, a 2.5GHz fully differential tuned LNA with integrated T/R switch is designed in a High-K metal gate 32nm digital CMOS process, and packaged in an SoC-compatible flip-chip package. Reliability constraints of the package severely limit the ability to depopulate soldering bumps, and RF components must be designed taking the bump location into account. The LNA achieves a 3.5dB NF, -5dBm P1dB at 2.5GHz while drawing 11 mA from a 1.8V supply. LNA performance is enabled by use of a push-pull topology that exploits the equal strength of p and n transistors to improve linearity, use of nested coupled inductors (NCI) for low-noise input matching and to reduce area. The T/R switch handles 34dBm of power with an insertion loss of 1.1dB at 2.5GHz. T/R switch performance is enabled by reuse of LNA gate inductor to enable low RX mode loss, use of remote body-contact ed TX switch with high power handling and ESD protection for a transformer coupled PA.