A Noise-Cancelling Receiver Front-End With Frequency Selective Input Matching

Abstract

This paper presents an inductor-less frequency selective input match wireless receiver front-end utilizing noise cancellation, operational from 0.7 to 3.8 GHz. The main path of the receiver consists of a high input impedance transconductance stage where the output is down-converted to baseband by current mode passive mixers, and then amplified to voltage by a transimpedance amplifier. The output voltage is converted into a current and frequency up-converted by a second set of transconductance stage and mixer. This current is then fed back to the input of the main path, reducing the input impedance, providing input match by means of negative feedback. An auxiliary path with digitally controllable gain is also introduced to cancel the noise of the main path while maintaining high linearity. The chip prototype is fabricated in a 65 nm CMOS process and occupies an active area of 0.15 mm $^2$ . It achieves a noise figure between 1.6 dB and 3.2 dB depending on the frequency of operation, and an out-of-band IIP2 and IIP3 better than +75 dBm and +1 dBm, respectively. The chip is supplied by 1.2 V and consumes 22.8–34.9 mA.