A 27-nW Wake-Up Receiver With a Quartz Transformer Matching Network Achieving −71.9-dBm Sensitivity and −46-dB SIR at 0.8% Offset

This work reports the first ultra-low power wake-up receiver (WuRX) to be integrated with a quartz micro-electromechanical systems (MEMS) transformer-based matching network (MN), achieving the best signal-to-interference ratio (SIR) compared to state-of-the-art sub-100 nW receivers. A quartz resonant piezoelectric transformer (PT) was chosen for its high loadedQ (~19,000), enabling large, passive voltage gain – a necessity for low-power radios where active RF amplification consumes too much power. Optimization of the CMOS envelope detector (ED) input impedance and number of ED stages preserves the highQof the preceding MEMS transformer while maintaining a high passive gain of 27 dB and a narrow bandwidth of 2 kHz at 50 MHz. The quartz PT is designed for maximum voltage gain from a50~Ωsource to the ED input. The 6-stage ED is designed with an input impedance greater than 1 MΩand a conversion gain of 264.9 V-1to maximize sensitivity without de-Qing the transformer. The WuRX is implemented in a 65-nm CMOS process and achieves a sensitivity of −71.9 dBm while consuming just 27 nW. The measured SIR is −46 dB at a 0.8% frequency offset due to the narrowband filtering from the transformer.