| Summary: | In this paper, a 2.4 GHz Bluetooth low energy receiver employing a power-efficient quadrature RF-to-baseband-current-reuse architecture is presented for low-power low-voltage internet of things applications. The proposed quadrature RF-to-baseband-current-reuse RF front-end consists of a low-noise transconductance amplifier, an active-type polyphase filter-based quadrature generator, transimpedance amplifiers, and double-balanced current-mode passive mixers on a single dc current path. An input matching network is used to perform power-constrained simultaneous noise and input power matching and 1/<inline-formula> <tex-math notation="LaTeX">$f$ </tex-math></inline-formula> noise reduction in the RF and baseband domains, respectively. The quadrature RF signals are provided to the single-quadrature mixers through an embedded active-type polyphase filter-based quadrature generator. The implemented Bluetooth low energy receiver is composed of the RF-to-baseband-current-reuse RF front-end, IF amplifiers, two-stage passive-<italic>RC</italic> polyphase filter, and fifth-order Chebyshev-II <inline-formula> <tex-math notation="LaTeX">$G_{m}$ </tex-math></inline-formula> <italic>-C</italic> filters. The proposed design was fabricated using a 65-nm CMOS process and characterized primarily in the Bluetooth low energy operating frequency bands. The active die area of the implemented receiver was 0.85 mm<sup>2</sup>, and the receiver drew a bias current of 1.41 mA from a nominal supply voltage of 0.8 V. The Bluetooth low energy receiver achieved a noise figure of 13.2 dB, conversion gain of 42 dB, image rejection ratio of more than 30 dB, and input-referred third-order intercept point of −25 dBm.
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