Design of CMOS class-E Power Amplifier for Low Power Applications

A fully integrated class-E power amplifier (PA) at 2.4 GHz implemented in a 0.18µm 6-metal-layer mixed/RF CMOS (complementary metal-oxide-semiconductor transistor) technology is presented. A two-stage amplification structure is chosen for this PA. The driving stage produces a high swing switch signal by using resonation technology. The output stage is designed as a class-E topology to realize the power amplification. Under a 1.2V power supply, the PA delivers a maximum output power of 8.8 dBm with a power-added efficiency (PAE) of 44%. A new power control method for the class-E power amplifier is described. By changing the amplitude and duty cycle of the signal which enters the class-E switch transistor, the output power can be covered from -3 to 8.8 dBm through a three-bit control word. The proposed PA can be used in low power applications, such as wireless sensor networks and biotelemetry systems.