Rugged HBT Class-C Power Amplifiers with Base-Emitter Clamping

摘要

The ruggedness of HBT Class-C power amplifiers was improved by adding ananti-parallel diode to the amplifier input to limit the negative swing of thebase-emitter voltage. The improved amplifier could withstand 3:1 instead of 2:1mismatch in CW operation, and 2.5:1 instead of 1.5:1 mismatch in pulseoperation. In contrast to other approaches with emitter ballast, activefeedback, or electrostatic discharge protection circuits, the present approachis simple to implement and has negligible impact on overall amplifier outputpower, gain or efficiency.