Patent ID: 8169759

Claim:
An apparatus comprising: an input terminal of a first transistor coupled to a port to receive a signal; a control terminal of the first transistor coupled to a source of an electrical potential; an output terminal of the first transistor configured to receive the signal from the input terminal through a channel induced by the electrical potential of the control terminal, the electrical potential of the control terminal being increased by the signal on the input terminal to render the channel more conductive between the input terminal and the output terminal, the input terminal, the control terminal, and the output terminal being configured to protect circuits coupled to the output terminal from electrostatic discharge from the port and to couple the signal to the circuits; and a second transistor coupled in parallel with the first transistor between the port and the circuits, the second transistor including a control terminal coupled to an internal supply voltage that is lower than an external supply voltage during a power down mode of operation when the signal is received.