IIP2-Calibration-Free Receiver Front End With Notch-Filtered Low-Noise Transconductance Amplifier for 5G New Radio Cellular Applications

This paper presents an input-referred second-order intercept point (IIP2)-calibration-free receiver (RX) front end with a notch-filtered low-noise transconductance amplifier (LNTA) for 5G new radio (NR) cellular applications. The LNTA adopts a proposed dual-band third-order LC notch filter with a band-switchable differential inductor with a center tap. It rejects transmitter leakage and out-of-band blockers. Consequently, the RX front end has enhanced blocker tolerance and meets the IIP2 requirement without any IIP2 calibration. The RX front end comprises the broadband LNTA with the dual-band LC notch filter, current-mode passive mixers with a 25% duty-cycle local oscillator signal, and transimpedance amplifiers. Fabricated through a 65 nm CMOS process, the RX front end was characterized primarily in the low band and mid band of 5G NR sub-6 GHz bands. It achieved a noise figure of 3.5 dB, conversion gain of 41.5 dB, out-of-band input-referred third-order intercept point of 2.1 dBm, and IIP2 of more than 59 dBm. It drew a bias current of 11.7 mA from a nominal supply voltage of 1 V. The active die area was 2.1 mm2.