2.4 GHz BLE Receiver With Power-Efficient Quadrature RF-to-Baseband-Current-Reuse Architecture for Low-Power IoT Applications

Abstract

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/ $f$ 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-RC polyphase filter, and fifth-order Chebyshev-II $G_{m}$ -C 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 mm2, 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.

Keywords

• Active-type polyphase filter
• bias-current sharing
• Bluetooth low energy
• current-reuse
• image rejection ratio
• IoT