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Semiconductor apparatus including a protection circuit against electrostatic discharge

  • US 5,442,217 A
  • Filed: 11/26/1993
  • Issued: 08/15/1995
  • Est. Priority Date: 12/01/1992
  • Status: Expired due to Term
First Claim
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1. A semiconductor apparatus including a protection circuit against electrostatic discharge, comprising:

  • an internal circuit;

    a terminal connected to the internal circuit;

    a ground wiring for applying a ground voltage to the internal circuit;

    a substrate bias wiring for applying a substrate bias voltage to a substrate in which the semiconductor apparatus is provided;

    at least one power supply wiring for applying a voltage having a different polarity from the polarity of the substrate bias voltage relative to the ground voltage;

    a first protection device against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection device being connected between the substrate bias wiring and the ground wiring;

    a plurality of second protection devices against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection devices being respectively provided between the terminal and one of the ground wiring and the substrate bias wiring, and between the power supply wiring and one of the terminal, the ground wiring and the substrate bias wiring; and

    a plurality of diodes respectively provided between the substrate bias wiring and the power supply wiring, between the substrate bias wiring and the terminal, and between the substrate bias wiring and the ground wiring, wherein the first and the plurality of second static electricity protection devices are each formed of a bipolar transistor.

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