A 6.1-nW Wake-Up Receiver Achieving −80.5-dBm Sensitivity Via a Passive Pseudo-Balun Envelope Detector

A wake-up receiver (WuRX) that achieves −80.5-dBm sensitivity with only 6.1 nW of power is presented. High sensitivity is achieved via a passive pseudo-balun envelope detector (ED) with a high input impedance (
$> 750~\text {k}{\Omega }\;{\|}{< }1.4$
pF) that enables a 30.6-dB passive voltage gain transformer while providing differential output and improving the conversion gain by
${2}{\times }$
compared to a conventional single-ended input passive ED for a given input capacitance. The WuRX is implemented in a 180-nm CMOS process and operates from a 0.4-V supply.