A cross-coupled switch-RC mixer-first technique achieving +41dBm out-of-band IIP3

Abstract

With the growing amount of wireless devices, interference robustness is a receiver specification of increasing importance. This paper presents a technique that improves both out-of-band compression and weakly non-linear distortion. It mitigates the effect of non-linearity in the baseband amplifier by preceding it by a cross-coupled passive filter. This provides a highly linear passive shunt path for out-of-band currents, while maintaining wideband input matching. The 65nm CMOS prototype chip achieves 41dBm out-of-band IIP3 at 40MHz offset and an 11dBm out-of-band blocker compression point. The chip has an area of 0.8mm2 and consumes 46mW from a 1.2V supply.