A circuit includes first through fourth transistors and a device. The first transistor has a control input and first and second current terminals. The control input provides a first input to the circuit. The second transistor has a control input and first and second current terminals. The control input provides a second input to the circuit. The third transistor has a control input and first and second current terminals. The fourth transistor has a control input and first and second current terminals. The second current terminal of the fourth transistor is coupled to the second current terminal of the third transistor, and the control input of the fourth transistor is coupled to the first current terminals of the first and second transistors. The device is configured to provide a fixed voltage to the control input of the third transistor.