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-Ω 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.