A 0.7 to 1 GHz switched-LC N-Path LNA resilient to FDD-LTE self-interference at ≥40 MHz offset

Abstract

This paper proposes a self-interference-resilient LNA for the FDD-LTE covering 0.7 to 1GHz. It incorporates a switched-LC N-path network with gain-boosting and optimum-biasing techniques to enhance the out-of-band (OOB) linearity at ≥40MHz offset. Implemented in 0.18µm SOI CMOS, the LNA achieves >31.2dB output rejection, +26.2dBm (+8dBm) OOB-IIP3 (iB1dB) at ≥40MHz offset and 6.8dB blocker NF at +4dBm blocker power for the default mode, while consuming a reasonable power of 48.4 to 62.5mW. When reconfigured to high-rejection mode, the LNA offers a tunable cancellation notch improving the output rejection to >50dBc.