Title :
A study of Class C operation of GaAs power HBTs
Author :
Ali, Farahiyah ; Gupta, Arpan ; Salib, M. ; Veasel, B.
Author_Institution :
Adv. Technol. Div., Westinghouse Electr. Corp., Baltimore, MD, USA
Abstract :
GaAs power HBTs are traditionally biased in Class A or Class AB mode for power amplifiers. This paper describes the tradeoffs of operating these devices in Class C bias. We find that power-added efficiency (PAE) improves and power gain decreases in Class C when compared to Class AB bias. At 6 GHz, the PAE increased by greater than 10 percentage points (from 68.9% in Class AB to 80.6% in Class C) with concurrent loss of 4.3 dB in power gain. The efficiency improves monotonically with lower operating frequency. In a single-tone environment, the second harmonic increases by /spl sim/7 dB in Class C over Class AB. To our knowledge, this is the first report on the experimental study of Class C operation of GaAs HBTs.<>
Keywords :
III-V semiconductors; gallium arsenide; heterojunction bipolar transistors; microwave bipolar transistors; microwave power transistors; power bipolar transistors; semiconductor device testing; 4.3 dB; 6 GHz; 80.6 percent; GaAs; class C operation; power HBTs; power amplifiers; power gain; power-added efficiency; second harmonic; single-tone environment; Breakdown voltage; Fingers; Gallium arsenide; Heterojunction bipolar transistors; MESFETs; Power amplifiers; Power supplies; Radio frequency; Radiofrequency amplifiers; Tuners;
Conference_Titel :
Microwave Symposium Digest, 1995., IEEE MTT-S International
Conference_Location :
Orlando, FL, USA
Print_ISBN :
0-7803-2581-8
DOI :
10.1109/MWSYM.1995.406006
