Fully Integrated CMOS Saturated Power Amplifier With Simple Digital Predistortion

A highly efficient CMOS saturated power amplifier (PA) is implemented. The efficiency is enhanced by the voltage waveform engineering using the second harmonic component generated by the nonlinear output capacitor (C
_out
). For an improved linearity to satisfy the specification of handset applications, a simple open-loop digital predisortion algorithm is employed. The fully integrated single-stage differential PA including the output transformer is fabricated using a 0.18- μm CMOS process. The PA with 3.5 V supply delivers good performance across the 1.7-2.0 GHz frequency band.