An electronic chip includes a chip core including an input terminal, an output terminal, an external pad, and an input-output circuit coupled to the chip core and the external pad. The input-output circuit includes an enable terminal coupled to the chip core, a connection terminal coupled to the external pad, a switchable diode device coupled between a supply voltage and a reference voltage, and a levelling circuit. The switchable diode device is coupled to the connection terminal and the enable terminal and is configured to operate as a diode in response to a control signal in a first state applied to the enable terminal and to operate as an open circuit in response to the control signal in a second state applied to the enable terminal. The levelling circuit is coupled to the connection terminal, the input terminal of the chip core, and the output terminal of the chip core.