A 1-V 5 GHz variable gain low noise amplifier in 0.18-μm CMOS

This paper describes a 1-V 5 GHz fully differential variable gain low noise amplifier (VGLNA) in a 0.18-mu m CMOS process. The LNA provides 50-Omega input impedance and utilizes a tuned load to provide high selectivity. The VGLNA achieves a maximum small signal gain of 10.11 dB within 1-dB compression point (iCPI(1dB)) of -16.0 dBm and a minimum gain of 1.6 dB within iCP(1dB) of -14.5 dBm. In the high gain and low gain modes, the noise figures (NFs) are 1.94 dB and 3.96 dB, respectively with good input return loss. The LNA's IIP3 in the high gain mode is -5.15 dBm. The LNA consumes only 64 mA of current from a 1-Vpower supply.