Fundamental Difference of Power Handling Between CE and CB HBTs

Abstract

Fundamental power handling of common-emitter (CE) and common-base (CB) (SiGe) power HBTs is compared by measuring their dynamic load lines under large-signal operation with input and output matched for maximum output power (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ). The distinct difference of load lines indicates the fundamental different power amplification mechanisms between the two configurations. It is shown that under voltage-source bias the CE configuration always provides higher (saturated) output power (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ) than the CB configuration, while higher power gain and power added efficiency (PAE) could be obtained from the CB configuration than the CE configuration before entering the power saturation region