A 30.8-dBm Wideband CMOS Power Amplifier With Minimized Supply Fluctuation

A wideband design method for a twisted eight-shape transformer is introduced with the design guidelines. The supply modulation effect caused by the fluctuation of virtual ground is analyzed. To minimize the effect, the different matching capacitors are adopted at each port and an accurate virtual ground is positioned. For verification, a fully integrated linear CMOS power amplifier (PA) is implemented in a 0.18-μm standard 1P6M RF CMOS process for 2.3- and 2.6-GHz m-WiMAX (IEEE 802.16e standard) system. In continuous-wave measurements, the two-stage Class-AB PA delivers 30.8-dBm saturated power with a 30.6% power-added efficiency (PAE) and 22-dB gain across 900-MHz bandwidth (defined as 1-dB gain bandwidth). In 16 quadrature amplitude modulation m-WiMAX modulation signal measurements, the PA generates 26.2-dBm average power with a 20.5% PAE. The PA complies with the spectrum mask at a 21-dBm average power level and satisfies 3% error vector magnitude at 17-dBm average power.