An integrated circuit includes a power supply terminal, a reference terminal, and a signal terminal. A first protection device is coupled between the signal terminal and the power supply terminal, the first protection device including a first MOS transistor. A second protection device is coupled between the signal terminal and the reference terminal, the second protection device including a second MOS transistor. Gates of the MOS transistors are directly or indirectly coupled to the reference terminal. Substrates of the MOS transistors are coupled to the reference terminal via a common resistor.