A 1.85GHz CMOS power amplifier with zero-voltage-switching contour-based outphasing control to improve back-off efficiency

A fully-integrated Watt-level output 0.13μm CMOS power amplifier (PA) based on zero-voltage-switching contour control is presented. The technique employs duty-cycle modulation in concert with outphasing to achieve up to 1.5 times improvement in back-off efficiency compared to conventional outphasing PA. The PA meets EVM and ACLR specifications for WCDMA and LTE 10MHz uplink signals with 29% and 21% PAE respectively.