SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

A semiconductor integrated circuit is provided to omit an ion implantation process for a critical value control by forming a gate dielectric of a MOS transistor in an input buffer. A positive high voltage over a source voltage is applied to a high voltage input terminal(50). A transfer gate(54) is comprised of a high-withstand voltage N-channel MOS transistor capable of withstanding the high voltage. An input of high-withstand voltage N-channel MOS transistor is connected to the high voltage input terminal and the source voltage is applied to a gate of the high-withstand voltage N-channel MOS transistor. An input buffer(52) includes a MOS transistor of which a gate is connected to an output of the transfer gate. A pull-up device(55) is connected to the output of the transfer gate and biases the output with the source voltage. An output transistor(53) is connected to the high voltage input terminal and is comprised of a high-withstand voltage N-channel MOS transistor capable of withstanding the high voltage.