0.4–6 GHz,17-dBm B1dB, 36-dBm IIP3 channel-selecting, low-noise amplifier for SAW-less 3G/4G FDD receivers

Abstract

A channel-selecting, low-noise amplifier (CSLNA) is presented that meets the requirements for a SAW-less diversity path receiver in frequency-division duplexing (FDD) cellular systems. An N-path filter is incorporated into the LNA feedback network to tune from 400 MHz to 6 GHz. The proposed CS-LNA creates close-in stopbands around the passband to suppress transmit (TX) blockers up to 17 dBm. This work reports an out-of-band (OOB) IIP3 of 36 dBm and IB IIP3 of 10 dBm with the maximum rejection larger than 60 dB. To the author's knowledge, this is the highest blocker rejection, power-handling capability and IIP3 for an LNA that is tunable over more than a decade.