A Linear Cmos Power Amplifier Using Class-D To Reduce The Number Of Required Inductors

We propose a linear class-D amplifier for the driver stages of RF CMOS linear power amplifiers. To minimize the chip areas for the driver stages of the linear power amplifiers, we propose a technique for the class-D amplifier to be operated as a linear amplifier. The linear gain and proper bias point for the linear operation are obtained with additional load capacitance and a feedback resistor, respectively. To verify the feasibility of the proposed linear class-D amplifier, we designed a 1.8-GHz CMOS linear power amplifier with a differential structure using 180-nm RF CMOS technology. From the measured linearity and maximum average output power with a WCDMA modulated input signal, we successfully verify the linear operation of the proposed linear class-D amplifier. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:565-569, 2016