Abstract: According to one embodiment, a semiconductor integrated circuit includes: a protection circuit including a first diode whose cathode is connected to a first wiring having a power-supply voltage and whose anode is connected to a first node, and a second diode whose anode is connected to a second wiring having a reference voltage and whose cathode is connected to the first node; a protection resistor that is connected to the first node at one end thereof and is connected to a second node at the other end thereof; a buffer circuit that is connected between the first wiring and the second wiring and has an input terminal to which a voltage at the second node is input; and a switching element that is connected between the first wiring and the second node.

Abstract: An input protection circuit for MOS devices includes a first resistor and a first parasitic bipolar transistor connected between an input pad and an input buffer circuit of a MOS device. The input protection circuit for MOS devices further includes a second resistor and a second parasitic bipolar transistor connected at a preceding stage of the input buffer circuit so that the gate oxide film of the input buffer circuit can be protected from being damaged by static charges or a voltage which is accidentally generated, without increasing the pattern size of the first parasitic bipolar transistor.