| 摘要 |
PURPOSE: To protect a plurality of inner circuits(IC) for processing signals covering from high frequency bands to low frequency bands from electrostatic breakdown due to positive/negative electrostatic charges. CONSTITUTION: In internal circuits operating at high frequency bands, a multi- stage connection protective circuit is incorporated, having a plurality of transistors connected as diodes which have low parasitic capacitances and never malfunction if an input signal over the power source voltage is applied. In internal circuits operating at low frequency bands, a protective circuit having a transistor connected as a diode is incorporated. The protective circuits takes each a two-line protective circuit constitution wherein currents for protecting the internal circuits flow in mutually opposite directions against positive and negative electrostatic charges.
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