A 45–2500 MHz high efficiency power amplifier with novel adaptive bias technique

Abstract

The adaptive bias technique is the common technology for improving the power-added efficiency (PAE) of the power amplifier (PA). However, the performance of the adaptive bias technique is sensitive to the frequency variation. This paper presents a novel adaptive bias as the common-source bias of the 45–2500 MHz CMOS PA, which combines the subthreshold PD to decrease the effect on frequency of adaptive bias technique and a unity gain amplifier to increase the detection sensitivity, for improving the PAE at back-off mode over the wide bandwidth. The proposed PA provides a good performance from 45 MHz to 2500 MHz, while the peak of the saturation output power is 24.02 dBm over the frequency band. Moreover, the maximum PAE achieves 44.61% at 500 MHz and the PAE is larger than 28.48% at 3 dB back-off power. The chip size of the broadband PA achieves 1.87 mm² at TSMC 0.18 um technology process. It draws 200 mA from 3.3 V supply voltage.