Comparator Based Envelope Tracking for RF PA Using FinFET

Energy efficient operation of power amplifiers (PAs) and thus preserving the battery charge for longer time is a growing concern for mobile devices without sacrificing linearity. The efficiency enhancement in radio frequency (RF) PAs is influenced by the supply modulator in the envelope tracking (ET) design. This paper presents the design of a FinFET based comparator that will form a base for designing a multilevel supply modulator that can trackthe RF input signal linearly and more precisely. A single-bit comparator has been designed that works at 3.5 GHz frequency with a minimal rise-time propagation delay of approximately 0.4 ps. The RF input signal strength is compatible with the comparator's swing of 0 - 1 V. A multilevel supply modulator design can significantly improve the power efficiency of RF P A resulting in extended battery life.