A Battery-Less Crystal-Less Event-Driven UWB Tag With Hybrid Power Management Network and PI-CDR-Based Wake-Up Receiver

Ultra-wideband (UWB) tags are widely used in inventory-management and location-tracking applications, where low-power and cost-effective connectivity are essential. In this work, we propose a battery-less and crystal-less UWB tag, composed of an ultra-low-power (ULP) wake-up receiver (WuRX) and an edge-combining all-digital UWB transmitter. The UWB tag employs a fully event-driven architecture, significantly reducing standby power consumption. Additionally, a fast-response phase-interpolation clock-and-data recovery (PI-CDR) circuit is integrated into the WuRX, which not only replaces the off-chip crystal oscillator but also tracks clock drift from the base station. Furthermore, the edge-combining all-digital UWB transmitter does not require a phase-locked loop (PLL) or an open-loop oscillator, enabling a fast startup time and low-power transmission. Implemented in 65nm CMOS, the proposed UWB tag achieves an energy harvesting (EH) sensitivity of –29dBm with a receiver active and standby power consumptions of 98nW and 8nW, respectively.