摘要 |
A protective circuit for a semiconductor integrated circuit having a MOS transistor is constructed of a protective device having a first conducting type of protective device region provided in the surface of a substrate and a second conducting type of first diffused part and second diffused part provided in the surface of the protective device region. The first diffused part is connected to a power line of the MOS transistor, and the second diffused part is connected to a signal line between an external input terminal and the MOS transistor. The bipolar operation of the protective device allows electric charge accumulated in the power line to be discharged from the external input terminal, and also allows electric charge accumulated in the external input terminal to be discharged from the power line. Accordingly, the occurrence of electrostatic breakdown in the semiconductor integrated circuit can be prevented.
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