CMOS Channel-Selection LNA With a Feedforward N-Path Filter and Calibrated Blocker Cancellation Path for FEM-Less Cellular Transceivers

In this article, a CMOS tunable channel-selection (CH-SEL) low-noise amplifier (LNA) with a feedforward (FF)
$N$
-path filter and a gain- and phase-calibrated interference- cancellation technique is proposed for advanced front-end module (FEM)-less cellular transceivers. The proposed LNA exhibits a high-
$Q$
RF bandpass/band-rejection filter characteristic based on a four-path filter, an active blocker cancellation with an FF translational loop, and an
LC
tank at the input, internal node, and output, respectively. The proposed gain- and phase-calibration block and tunable high-pass filter in the FF filtering path adjust the notch frequency corresponding to the transmitter leakage signal and help realize sharp notch filtering. The proposed CH-SEL LNA with CMOS duplexers compensates for the limited filtering performance of the CMOS duplexer and improves the blocker-tolerance and linearity of the receiver, and thus, can replace surface acoustic wave duplexers in the FEM. Fabricated in the 65-nm CMOS process, the CH-SEL LNA achieves a maximum voltage gain of 19.3 dB, minimum NF of 5.1 dB, and notch rejection ratio of more than 27.8 dB. It can also cover mid-band frequencies in the range of 1.35–2.7 GHz for 5G new radio cellular applications, exhibits an average current of 20 mA from a supply voltage of 1 V, and has an active die area of 1.16 mm
²
.