Abstract
Wake-up receivers (WuRX) present an opportunity to reduce average power consumption of IoT transceivers, however achieving sensitivity and interferer tolerance while providing wideband matching and sharing an antenna interface present a significant challenge for existing architectures. This paper 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. The paper analyzes gain/power trade-offs 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 mm (2). The primary RX achieves 3.8 dB NF and 0.75 dBm out-of-band P1dB with 440μW power consumption. The WuRX achieves -86 dBm sensitivity for 10kb/s data rate and up to -40 dB signal-to-interferer ratio (SIR) with 171μW power consumption.