A 4.4- $\mu$ W Wake-Up Receiver Using Ultrasound Data

In wireless sensor nodes, using a wake-up receiver to duty-cycle the main receiver significantly reduces the overall power consumption of the node, as long as the power consumption of the always-ON wake-up receiver is very low. We demonstrate line-of-sight ultrasound data communications for ultra-low power wireless wake-up in sensor networks. The 65-nm CMOS 0.6-V receiver prototype achieves a BER of better than 10^-3 measured for a 250-bps free-space 8.6-m link in an indoor environment while dissipating only 4.4 μ W and requiring only - 18 dBm electrical power to be delivered to the transmit transducer.