Amplifier withStrong ImmunitytoInterferers

A variable-gain low-noise amplifier withcapacitive stepattenuators ispresented. Thegainisdigitally controlled by current splitting technique ofcascode transistors forlinearity requirements. Thefabricated LNA showed11P3increase of-1.1 to3.5dBm atgainof25.8to21.2dB,respectively, widegain rangeofover42.7dBbycapacitive attenuators, NF of1.5dBat 650MHz,andpowerconsumption of15.4mW with2.9Vsupply voltage using a0.5-pm BiCMOSprocess.