A 400M-510MHz On-Chip Transformer-Based RF Power Amplifier with 22.5dBm Output Power and 48% PAE

RF power amplifiers are essential components in wireless transceivers. In this paper, a high-efficiency RF power amplifier circuit for medium to long-range wireless communication (CSS modulation) is designed. To achieve high-efficiency performance metrics, a differential Class E architecture and on-chip transformer matching are employed. At low supply voltages, the impedance transformation ratio is large, and the higher loss is caused by the low-Q on-chip inductance. A differential Class-E structure is adopted to share the large current in the circuit, reducing power loss in passive devices. Additionally, on-chip transformers are used for power synthesis and impedance transformation in the differential circuit. Compared to traditional RF power amplifiers, this paper optimizes the driving amplifier circuit, differential Class E amplification circuit, and on-chip transformer circuit in combination. The chip area is approximately 1.2mm ² . Post-simulation verification was performed on the circuit based on the SMIC55nm process, with a power supply voltage of 1.5V and an operating frequency of 400M~510MHz. It achieved a power output of 22.5dBm and a PAE of 48%.