A low-power impulse-radio ultra-wideband (IR-UWB) receiver using the super-regenerative principle is employed. The input carrier frequency of the receiver is 4.5GHz with a data rate of 4Mbps. An asymmetric LC-VCO is used for reducing the oscillation start-up time. To minimize receiver complexity and reduce energy consumption, a non-coherent SRR architecture with internal quench signal is designed. Locking of the quench signal with the input RF signal is verified by simulation and measurement. The fabrication technology used is 0.18μm BiCMOS but only CMOS transistors are used. The energy dissipation is 0.9nJ/bit.