This paper presents a low-power Bluetooth 5.1 and Bluetooth low energy compliant receiver. The receiver has two modes of operation: a low-power mode, and a high-performance mode. It utilizes various techniques for low power consumption at both system and circuit levels. For example, it uses a Low-IF mixer-first architecture to optimize power consumption at system level. In addition, it uses harmonic down-conversion in the low-power mode to enable quadrature local oscillation generation. Circuit-level power minimization techniques include using reduced supply voltages, 500 mV for the VCOs and 700 mV for the front end; using passive mixers; and reusing the biasing currents.