A 5 GHz CMOS Variable Gain Low Noise Amplifier for wireless LAN Applications

This paper describes a 5 GHz fully differential variable gain low noise amplifier (VGLNA) in a 0.18-mum CMOS process. The LNA provides a 50-Omega input impedance and utilizes a tuned load to provide high selectivity. The VGLNA achieves a maximum small signal gain of 12.34 dB within 1-dB compression point (iCP_1db) of -12.0 dBm and a minimum gain of 6 dB. In the high gain mode(HGM) and low gain mode (LGM), the noise figures (NFs) are 3.89 dB and 4.25 dB, respectively with good input return loss. The LNA´s IIP3 in the HGM is - 1.24 dBm. The LNA consumes only 5.79 mA of current from a 1.5-V power supply.