A Novel High Efficiency and Linearity Power Amplifier with Over-Voltage Protection

This paper presents a power amplifier (PA) design to improve linearity by using a novel power cell compensating the main nonlinear sources from the power devices and to improve the overall efficiency by a dynamic DC biasing circuit. An over-voltage protection circuit to ease output mismatch induced problems is included in this PA design. As a case study, this power amplifier is implemented with InGaP/GaAs HBT operating at 1880 MHz. The CDMA standard is used to evaluate its linearity and efficiency. The P1dB is improved from 30 dBm to 32 dBm and the cumulated output current is much improved in a wide output power range. The ACPR and ALTR at 28 dBm output power level are improved by 5 dB and 12 dB with the novel PA respectively. The over-voltage protection circuit works well under output mismatch conditions.