Wideband variable gain amplifier with noise cancellation

A 1-5-GHz noise-cancelling variable gain amplifier is presented in 0.18--m CMOS technology that achieves a low noise figure (NF) below 4.8-dB over an 11-dB gain range. Its NF is as low as 3.2-dB for the gain range of 5.5 to 11-dB, while its input return loss is better than 13-dB over the entire gain range of -5 to 11-dB. The measured input-referred two-tone third-order intercept point (IIP3) at 2.4-GHz is better than 0 and -4.5-dBm at minimum and maximum gain, respectively. The circuit occupies an area of only 0.067-mm² and consumes less than 19 mW of power from a 1.8 V supply.