1. A device comprising: a package that includes a terminal; an active transistor die coupled to the package and electrically coupled to the terminal; a detector, coupled to the package and electrically coupled to the terminal, and configured to sense a signal characteristic on the terminal; and control circuitry, coupled to the package and electrically coupled to the active transistor die and to the detector, wherein the control circuitry comprises a control device that includes a temperature sensor coupled to the package and is configured to acquire the signal characteristic from the detector, detect a package temperature, and based on the signal characteristic and the package temperature, to control in which of multiple operating states the device operates.