Sub-6 GHz Noise-cancelling Balun-LNTA with Dual-band Q-enhanced LC Notch Filter for 5G New Radio Cellular Applications

Abstract

This paper presents a blocker-tolerant broadband balun-low-noise transconductance amplifier (LNTA) with a high-Q dual-band LC notch filter for 5G new radio (NR) sub-6GHz cellular applications. The proposed balun-LNTA employs a noise-cancelling 1:5 CG-CS balun-LNA topology with local feedback gm-boosting and modified current-bleeding techniques to support entire bands of sub-6 GHz 5G NR application with less than 5 dB NF performance and balanced output of balun-LNTA. The dual-band Q-boosted LC notch filter with a band-switchable differential inductor is also proposed to enhance blocker tolerance of the receiver by removing out-of-band blockers and strong transmitter leakage signals. Simulated in a 65-nm CMOS process, the designed balun-LNTA achieves a minimum noise figure of 2.38 dB, a maximum transconductance gain of 44 mS, an S11 of less than -10 dB over the frequency range of 50 MHz-6 GHz, an input-referred third-order intercept point of 1.82 dBm, and blocker rejection ratios of more than 15 dB. It consumes 5.9 mA from a nominal supply voltage of 1 V. Its active die area is 0.55 mm².