摘要 |
Disclosed is a protection circuit capable of avoiding breakdown of a gate insulating film of a MOSFET and having an appropriate snap-back voltage in terms of reliability. In order to prevent breakdown of a gate insulating film of a MOSFET constituting a stacked protection circuit caused by application of a surge voltage between the gate and the drain of the MOSFET, a single or a plurality of diodes or a MOSFET switch is connected between the gate and the drain of the MOSFET for absorbing the surge voltage. The particular construction permits obtaining a large surge tolerance against the surge voltage entering through, for example, the external power source pad, making it possible to form a protection circuit used in I/O's tolerant to other power sources having an appropriate snap-back voltage against the external surge in assuring the reliability of the semiconductor device.
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