An output load VSWR (voltage standing wave ratio) protection circuit for SiGe power amplifiers (PA) is presented by using the relatively low collector-emitter avalanche breakdown characteristic of SiGe HBT. Unlike the conventional diode-type switch, the new protection circuit completely eliminates the undesirable dc leakage current during the normal operation of the PA. Simulations and measurements show the proposed protection circuit enhances the ruggedness of the PA at harsh operating condition while it imposes only minor performance degradation at normal operating condition.