AMPLIFIER CIRCUIT

摘要

An improved bipolar transistor power amplifier circuit including a bias input node, an RF input node, an RF output node, and a plurality of HBTs. Each HBT includes a base, an emitter, a collector, a base resistor connected to the base and selected to offset a portion of the voltage drop across the base and emitter of each transistor, an emitter resistor connected to the emitter, and a base capacitor having two electrodes one of which is coupled to the base. The HBTs are grouped together in two or more groups and each group includes a base resistor selected to offset another portion of the voltage drop across the base and emitter of the transistors. The base resistors are coupled to the bias input node, the collectors of each HBT are coupled to the RF output node, and the other electrode of each base capacitor is coupled to the RF input node resulting in a power amplifier with HBT base resistors which do not have to be large enough to provide all of the thermal protection and do not have to dissipate as much power resulting in a more compact layout.