Abstract: A semiconductor device of the present invention includes: a P-type output transistor configured to have a source to which a power supply voltage is applied, and a drain connected to an external connection pad; a gate wiring configured to be connected to a gate of the output transistor; a signal transmitting portion configured to transmit an input signal to the gate wiring; and a voltage-breakdown protecting portion configured to apply the power supply voltage to a back gate of the output transistor if a voltage on the external connection pad is equal to or lower than the power supply voltage, or the voltage-breakdown protecting portion bringing the signal transmitting portion into a disconnection state and applies the voltage on the external connection pad to the gate and the back gate of the output transistor if the voltage applied on the external connection pad is higher than the power supply voltage.

Abstract: A semiconductor device of the present invention includes: a P-type output transistor configured to have a source to which a power supply voltage is applied, and a drain connected to an external connection pad; a gate wiring configured to be connected to a gate of the output. transistor; a signal transmitting portion configured to transmit an input signal to the gate wiring; and a voltage-breakdown protecting portion configured to apply the power supply voltage to a back gate of the output transistor if a voltage on the external connection pad is equal to or lower than the power supply voltage, or the voltage-breakdown protecting portion bringing the signal transmitting portion into a disconnection state and applies the voltage on the external connection pad to the gate and the back gate of the output transistor if the voltage applied on the external connection pad is higher than the power supply voltage.