Power amplifier with a protection circuit

Power amplifier having a plurality of transistors (503, 504, 505), which are connected in a multiple stage to form the power amplifier (500), and a protection circuit (100) connected to the collector of the last stage transistor (505) and via a capacitor (547) to the base of the last stage transistor (505) of the plurality of transistors, wherein the protection circuit (100) generates a feedback current (I f1 ) which is applied to the capacitance upstream of the base, when a voltage (V 4 ) at the collector of the last stage transistor (505) exceeds a threshold set by the protection circuit (100).