Disclosed is an integrated circuit amplifier having a power transistor with a signal/bias input terminal, a first high current terminal, and a second high current terminal, and thermal protection circuitry with a sensor transistor having a sensor control terminal, a sensor output terminal, and a sensor current terminal coupled to a fixed voltage node. Sensor bias circuitry includes a sensor bias terminal coupled to the sensor control terminal, wherein the sensor bias circuitry is configured to generate a temperature set point at which a sensor output voltage at the sensor output terminal drops at least 50% when the temperature of the sensor transistor is above the temperature set point. Shutdown circuitry coupled between the sensor output terminal and the signal/bias input terminal is configured to reduce a bias signal at the signal/bias terminal in response to the at least 50% drop in sensor output voltage.