Two-Stage Compact Wideband Flat Gain Low-Noise Amplifier Using High-Frequency Feedforward Active Inductor

Abstract

In this article, a wideband differential low-noise amplifier (LNA) for multiband wireless communication applications is proposed. First, shunt peaking is implemented with a self-biased active inductor (AI) to realize wideband characteristics in a compact size. Second, a cross-coupled capacitor is added to the AI, thus constructing a feedforward path. It adds a signal to the output node so that the bandwidth (BW) can be further increased by compensating the gain reduction according to the frequency. Additionally, the feedforward path creates another feedback loop, generating a negative capacitance. The negative capacitance can cancel parasitic capacitance to increase BW with a cascade amplifier. The prototype LNA is fabricated with a 65-nm CMOS process. It has a gain of 26.7 dB and a BW of 4.1 GHz. The noise figure (NF) is 3 dB and the third-order input intercept point (IIP3) is −14.2 dBm at 2 GHz. It consumes 13.9 mA at a 1-V supply and has an area of 0.009 mm2.