21.4 A 0.75-to-1GHz Passive Wideband Noise-Cancelling 171µW Wake-Up RX and 440µW Primary RX FE with -86dBm/10kb/s Sensitivity, 35dB SIR and 3.8dB RX NF

IoT transceiver deployments are envisioned to have low power, low data-rate (~kb/s) wake-up receive (WuRX) and Mb/s primary receive (RX) modes for long battery lifetimes [1]. WuRX architectures based on energy-detection (ED) achieve ultra-low power (ULP) consumption but have poor sensitivities (~ -60 to -40dBm) for <; 1ms latency [2-5] and are susceptible to modulated interferers without passive high-Q RF filtering [6-9]. While modulated-interferer tolerance is critical for practical deployments, high-Q RF filtering severely limits operating frequency range, making it challenging to operate across region-specific spectrum allocations and temperature/process variations. Mixer-first uncertain-IF RX can potentially improve operating frequency range and interferer tolerance [10]. However, if the relatively high NF is mitigated using frequency-selective passive RF voltage gain, frequency operation range is again limited. Finally, the antenna must be shared between the primary RX, WuRX and potentially the TX in such ULP radios making it challenging to share the high-Q WuRX matching network with the fullband primary radio. This paper presents a low-power hybrid-coupler based mixer-first noise-cancelling RX that supports a wideband shared antenna interface for the primary and WuRX while also providing passive voltage gain and achieves (i) wide LO-defined operating bandwidth (0.75GHz to 1GHz) in both primary and wake-up modes, (ii) interferer-tolerance for the wake-up RX ( >26dB Signal-to-Interference Ratio (SIR) at 2MHz offset for 4Mb/s QPSK interferer) and high-linearity in the primary RX (0.75dBm IP1dB) and (iii) high-sensitivity in both wake-up (-86dBm) and primary RX (3.8dB NF) modes through noise cancelling, while consuming 171uW in wake-up RX mode (including RF LO) and 440uW in primary RX mode.