An 8.5pJ/bit Ultra-Low Power Wake-Up Receiver Using Schottky Diodes for IoT Applications

In this paper, we present an always-on ultra-low power (ULP) wake-up receiver (WuRx) that constantly listens to the channel. We propose a two-phase WuRx architecture resulting in a 12% reduction in the average power consumption compared to conventional single-phase architectures. The first phase detects the existence of a signal and triggers the second phase responsible for signature detection. A CMOS integrable Schottky diode is proposed for power detection utilizing passive gain from impedance matching network. In the second phase, we propose a novel, low power data-locked startable oscillator to correlate the received data with predefined signature, which avoids the use of power-hungry crystal oscillator and features 1nW/kHz efficiency. The proposed system operates at 750MHz and achieves a low wake-up latency of 200µs, a -50dBm sensitivity at a data rate of 200 kbps, a 1.69 µW average power and achieves a FOM~8.5pJ/bit. The system is implemented in 65nm CMOS technology and occupies an area of 1mm×0.75mm.