Design of dual band SiGe HBT LNA with current reuse topology

This paper presents a general methodology to design a LNA with current reuse topology for two standards which can operate at mobile band of 1.8GHz and WLAN band of 5.2GHz. A novel current reuse topology is proposed to reduce the power consumption and enhance the transmission gain. The input matching is achieved through serial and parallel LC circuit. Inductor degeneration in emitter is introduced to decouple the input impedance from the noise factor. The proposed LNA is designed in JAZZ SiGe HBT 0.35μm process. It achieves transmission gains of 30dB and 20dB, noise figures of 2.1dB and 1.7 dB respectively at 1.8GHz and 5.2GHz. And both S11 are below 17dB. The power consumption is 24.5mW under a power supply voltage of 3.5V.