2.4-GHz Bluetooth Low Energy Receiver Employing New Quadrature Low-Noise Amplifier for Low-Power Low-Voltage IoT Applications

In this article, a 2.4-GHz Bluetooth low-energy (BLE) receiver employing a new quadrature low-noise amplifier (LNA) is presented for low-power low-voltage Internet of Things (IoT) applications. The proposed quadrature LNA consists of a common-source (CS) amplifier with inductive degeneration, an active-type poly-phase filter (PPF), and an LC tank. The proposed active-type PPF between the CS amplifier and the LC tank provides quadrature generation, and the CS amplifier determines and optimizes the overall LNA performance parameters. Moreover, the proposed active-type PPF shares the dc bias current with the CS amplifier, thereby eliminating the necessity for additional current consumption. The implemented BLE receiver is composed of the quadrature LNA, a G
_m
-stage, a double-balanced current-mode passive mixer, a transimpedance amplifier, and an active-RC complex bandpass filter. The proposed design was fabricated in a 65-nm CMOS process and mainly characterized in the BLE operating frequency bands. The receiver achieves a noise figure of 8.2 dB, a conversion gain of 49.5 dB, an image rejection ratio of more than 33 dB, and an IIP3 of -25.75 dBm. The active die area of the implemented receiver is 1.16 mm
²
, and it draws a bias current of 2.7 mA from a nominal supply voltage of 0.8 V.