| 摘要 |
PROBLEM TO BE SOLVED: To obtain an input/output buffer circuit that can receive a higher potential input signal than a drive power supply voltage without the need for using a high breakdown voltage transistor(TR). SOLUTION: A normal transistor(TR), not a high breakdown voltage TR, is employed for a PMOS TR MP1 and an NMOS TR MN1 configuring an output driver and a resistor 20 is inserted between drains of the MOS TRs and an external terminal 17. Furthermore, the resistor 20 has a resistance that the drain potential of the PMOS TR MP1 and the NMOS TR MN1 is equal to an applicable voltage of the MOS TRs or below and is equal to a threshold potential of an input buffer 16 or over and causes a fall of the potential when a current path from the external terminal 17 to a power terminal 12 via a parasitic diode 15 of the PMOS TR MP1 is formed.
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