LAUSR

Wake-up receivers (WuRXs) present an opportunity to reduce the average power consumption of Internet-of-Things (IoT) transceivers; however, achieving sensitivity and interferer tolerance, providing wideband matching, and sharing an antenna interface present a significant challenge for existing architectures. This article presents a primary/WuRX which utilizes a quadrature hybrid coupler-based $N$ -path mixer first architecture to simultaneously achieve low noise, wideband matching, and a shared antenna interface. The passive-mixer first approach and a two-code modulated multi-tone signaling scheme provide interferer tolerance in the WuRX. This article analyzes gain/power tradeoffs in the proposed architecture in the context of noise impact with multi-tone WuRX signaling. The proposed architecture is implemented in 65-nm CMOS and occupies 2.25 $\text {mm}^{2}$ . The primary RX achieves 3.8-dB NF and 0.75-dBm out-of-band P1dB with 440- $\mu \text{W}$ power consumption. The WuRX achieves −86-dBm sensitivity for 10-kb/s data rate and up to −40-dB signal-to-interferer ratio (SIR) with 171- $\mu \text{W}$ power consumption.