A power controlled RF CMOS class-E PA with 43% maximum efficiency in 2.2 GHz

Abstract

This paper proposes a 2.2 GHz CMOS Power Amplifier (PA) useful to S-Band applications with an effective 3-bit output power control for efficiency improvement. It is composed by a cascode amplifier topology to minimize the voltage stress across the power transistors, being the cascode amplifier composed by four parallel branches, where the state (on or off) of 3 branches is separately activated by a 3-bit input, for efficiency control. It was designed for the 1 W output power range in 130 nm CMOS process. Post-layout simulations resulted a peak output power of 28.1 dBm (near 650 mW) with a maximum output power efficiency around 43% under 3.3 V of supply voltage. The 3-bit control allows a total output power dynamic range adjustment of 5.7 dBm, divided in 7 steps, with the efficiency changing from 25.4% to 43.7%.