Single-Ended CMOS Doherty Power Amplifier Using Current Boosting Technique

Abstract

In this letter, an efficiency enhancement technique incorporating a gate-voltage boosting of a peaking power amplifier (PA) in a CMOS Doherty PA is presented. To compensate the current driving capability from the low dc bias point of the peaking cell, an auxiliary bias network consisting of an operational amplifier (OPA) is utilized to provide the corresponding gate voltage in accordance with an instantaneous output power level. To verify the superior performance of the proposed technique, a CMOS Doherty PA with a prototype OPA has been fabricated using a commercial 0.18 $\mu{\rm m}$ process. The experimental results show that the implemented PA has an overall efficiency of 43.6% and a gain of 27.2 dB at an average output power of 25.2 dBm for a 10 MHz 3G LTE signal with a 7.6 dB peak-to-average power ratio (PAPR). Under this situation, the spectral performance is $-$ 34.1 dBc.