Semiconductor integrated circuit device

摘要

An inventive semiconductor integrated circuit device includes: an external connection terminal; an electrostatic discharge protection circuit; an output circuit; an output prebuffer circuit; an input prebuffer circuit; an internal circuit; an inter-power supply electrostatic discharge protection circuit; and a substrate potential control circuit. The substrate potential control circuit includes a capacitor and a resistor. The inter-power supply electrostatic discharge protection circuit includes an NMIS transistor. When a positive surge is applied to the external connection terminal, the substrate potential of the NMIS transistor is also increased. Thus, the NMIS transistor is turned ON, and the positive electrical charge supplied to the external connection terminal is discharged toward a ground line.