A power amplifier protection circuit that includes protection circuitry to
variably shunt an input radio frequency (RF) signal to AC ground, turn
off bias to an output transistor of a power amplifier, and turn off the
output transistor. The power amplifier protection circuit features an
asymmetrical control that can quickly shut off a power amplifier, and
turn on the power amplifier at a steady, controlled rate when an output
transistor exceeds a predetermined threshold voltage.