The highest signal level that can be applied to the input of a circuit without risk of
damaging the circuit.
Each GaAs FET or bipolar transistor has its own unique ability to withstand
excessive input power levels. This capability is related to device geometry, metal
thickness, fabrication techniques and materials. Since the input circuit of most
transistor amplifiers is tuned for maximum power transfer, the power withstanding
capacity of an amplifier is practically the same as that of the input transistor or
transistors.
If excessive power is applied to a transistor amplifier, the fast measurable affect is
almost always an increase in noise figure. A somewhat higher power will further
degrade noise figure and decrease the gain of the amplifier. If the input power
level is even higher, the input transistor will ultimately fail.
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