A 28-nm CMOS Sub-Microwatt IoT Wake-Up Receiver Utilizing an Ultra-Low-Power Event-Driven Ring Oscillator

This paper presents an ultra-low-power wake-up receiver (WuRx) designed in 28-nm CMOS for Internet of Things (IoT) applications. To minimize the standby power consumption of the IoT node, the proposed WuRx utilizes an event-driven ring oscillator (ED-RO) that remains completely inactive until triggered by an incoming RF envelope. The RF front-end consists of a highly sensitive passive envelope detector followed by a low-power baseband amplifier. Upon detecting an incoming signal, the ED-RO starts up instantly within 12 nanoseconds, generating the clock required for the digital correlator to decode the wake-up packet. Operating at a scaled supply voltage of 0.6 V, the entire WuRx consumes only 420 nW in standby mode. Under 2.4-GHz On-Off Keying (OOK) modulation at a data rate of 100 kbps, the receiver achieves a sensitivity of -53 dBm. The proposed event-driven paradigm effectively eliminates the continuous power consumption of local clock generation, making it highly suitable for perpetually powered or battery-constrained IoT devices.