A broadband differential cascode power amplifier in 45 nm CMOS for high-speed 60 GHz system-on-chip

A compact two-stage differential cascode power amplifier is designed and fabricated in 45 nm standard LP CMOS. The cascode configuration, with the common gate device placed in a separate P-well, provides reliable operating condition for the devices. The amplifier shows 20 dB small-signal gain centered at 60 GHz with a flat frequency response and 1-dB bandwidth of 10 GHz. The broadband large-signal operation is also ensured by providing constant load resistance to both stages over the entire band and coupling them with a dual resonance matching network. The chip delivers 11.2 dBm output power at 1-dB compression and up to 14.5 dBm power in saturation. The power amplifier operates with 2 V supply and draws 90 mA total current which results in 14.4% maximum PAE. The output third order intercept point is measured to be 18 dBm for two-tone measurement at 60 GHz with 0.5 GHz, 1 GHz and 2 GHz frequency separations.