2.4 GHz Low-power Receiver Front-end Employing I/Q Mixer with Current-reused Quadrature Transconductor for Bluetooth Low Energy Applications

Abstract

In this paper, a 2.4 GHz Bluetooth low energy (BLE) receiver front-end with a new inphase/quadrature (I/Q) down-conversion active mixer employing a current-reused quadrature transconductor is presented for low-power low-voltage Internet of Things applications. In the proposed I/Q mixer, the current-bleeding circuit, whose main role is to reduce the flicker noise in the switching stage, enhances the overall transconductance and provides quadrature signals with the main quadrature transconductor. Consequently, it improves the conversion gain and noise figure of the mixer without additional power consumption. The proposed BLE receiver front-end consists of a current-reused push-pull low-noise amplifier and an I/Q mixer with a current-reused quadrature transconductor. Simulated in a 65 nm CMOS process, the designed receiver front-end achieves a noise figure of 3.3 dB, conversion gain of 37.6 dB, and input-referred third-order intercept point of -22.73 dBm. It draws a bias current of 1 mA from a nominal supply voltage of 1 V. The active die area is 0.5 mm².