| 摘要 |
PURPOSE:To prevent degradation due to abnormal input overvoltage by inserting two protective elements between a base and a signal input terminal. CONSTITUTION:The two protective elements 100, 200 are inserted to an input circuit from the input terminal 6 of an IC. When the abnormal overvoltage having positive polarity is applied to the terminal 6, the voltage is clamped by a reverse direction diode consisting of an N type resistance layer 28 of the protective element 100 and a P type substrate 10 while being dropped by the N type resistance layer 28 and a P type resistance layer 32 of the protective element 200. A diode composed of the P type resistance layer 32 and an N type epitaxial growth layer 15 is forward bypassed at the same time, and bypassed by the junction capacity of the growth layer 15 and the P type substrate 10. When the abnormal voltage having negative polarity is applied to the terminal, the diode consisting of the N type resistance layer 28 and the P type substrate 10 is forward bypassed, and the abnormal overvoltage is not applied to a transistor 1. |
