A 2.5GHz Switched-Capacitor Power Amplifier with High Efficiency for BLE in 55nm CMOS Process

A fully integrated switched-capacitor power amplifier (SCPA) adopts switched-capacitor technology in Polar structure is proposed to achieve high linearity and high efficiency in this paper. This SCPA is applied to Bluetooth Low Energy (BLE) in 55 nm CMOS process and occupies an area of 0.67×0.35 mm². In order to reduce the area of the transceiver chip, the SCPA shared the matching network with low noise amplifier (LNA). The SCPA uses an array of small Unity-cell PAs that are recess connected in parallel according to a digital code word. The control signal is generated by thermometer decoder to control output power and output efficiency. The simulation results show that the peak output power is more than 6dBm and the peak drain efficiency is more than 29% at 2.5GHz. The isolation from SCPA to LNA is 17.6dB at 2.5GHz and the total power consumption is 13.2 mW.