High-efficiency CMOS stacked-FET power amplifier for W-CDMA applications using SOI technology

A linear CMOS power amplifier (PA) is developed for wideband code-division multiple-access (W-CDMA) application using 0.18 mu m silicon-on-insulator (SOI) technology. By adopting a quadruple-stacked FET structure, 1W of output power is achieved at 4V supply voltage. A negative capacitance circuit is employed to maximise the efficiency of the PA by cancelling out the excessive capacitance at the source terminal of the common-gate stage. Besides, a lineariser based on the variable capacitor circuit is added to reduce the inherent AM-PM distortion of the CMOS FET. Using W-CDMA modulation at 837MHz, the fabricated PA module delivers a PAE of 47.5% and an adjacent channel leakage ratio of -36dBc at the output power of 27.1dBm.