100-nW Wake Up Receiver With -42.3 dBm Sensitivity for Real-Time Location Systems

This paper presents a Wake-up Receiver (WuR) with Ultra-Low Power (ULP) consumption for a Real-Time Location System (RTLS). A novel method for its always-on mode is proposed that operates without using any active amplifiers that results in an ULP operation. The proposed WuR employs a D-flip-flop configuration, a peak detector and clock comparator with a minimal power consumption. In addition, it uses an On-Off Keying (OOK) modulation scheme. The WuR is designed for an ULP OOK-based transceiver that requires a minimum sensitivity of -42.3 dBm and operates at a frequency of 2.4 GHz. To feature a wide input power supply voltage operation, a current-biasing technique is employed to ensure the required sensitivity, consistently, over a wide input power range. The proposed design achieves power consumption as low as 100 nW while it operates over a wide range power supply of 680–900 mV. Moreover, the proposed WuR occupies a small die area of $100~\mu $ m by $50~\mu $ m due to the lack of active amplifiers