A 550–1050MHz +30dBm class-E power amplifier in 65nm CMOS

A 65nm CMOS broadband two-stage class-E power amplifier (PA) using high voltage extended-drain devices is presented. To reduce the peak drain-source voltage and improve reliable operation, sub-optimum class-E operation is applied. The PA is followed by a broadband output matching network implemented as an off-chip two-stage LC ladder. The measurements with a 5.0V supply voltage for the power stage and 2.4V for the driver stage show a drain efficiency > 67% and a power-added efficiency (PAE) > 52% with a Pout > 30dBm within 550MHz–1050MHz. The output power variation is within 1.0dB and efficiency variation is less than 13%. The highest efficiency is observed at 700MHz with peak drain efficiency of 77% and peak PAE of 65% at a Pout of 31dBm and 17dB power gain. By using dynamic supply modulation, the PA achieves a PAE of 40% and a drain efficiency of 60% at 10dB power back-off from 30dBm.