A 40% PAE linear CMOS power amplifier with feedback bias technique for WCDMA applications

A highly efficient CMOS linear power amplifier for WCDMA applications with feedback bias technique is presented. The method involves connecting the gates of common-gate devices of the driver stage and the power stage in cascode configurations by a feedback network for enhancing linearity. To achieve high efficiency and linearity simultaneously, large-signal IMD minimum (IMD sweet spot) is properly used at the desired output power level. The proposed PA was fabricated in a 0.18-µm CMOS technology. The experimental results demonstrate a gain of 26 dB, a maximum output power of 26 dBm with 46.4% of peak PAE, and a linear output power of 23.5 dBm with 40% PAE using a 3GPP WCDMA modulated signal. Both simulation and measurement results show an excellent large-signal IMD minimum at the output power using a WCDMA modulated signal.