Semiconductor integrated circuit

Abstract

Abstract PURPOSE:To isolate an internal circuit from the noise caused by the overvoltage applied to an input-output terminal by a method wherein the power source terminal and the earth terminal of the internal circuit are provided separately from those of a protective circuit and an input circuit. CONSTITUTION:When an overvoltage is applied to input terminals 4a and 4b and an output terminal 5, noise is generated on the power source terminal 2a and the earth terminal 3a to be connected to input protective circuits 6 and an output circuit 8, and the noise is transferred to a power source terminal 2b located inside a chip 1, an earth terminal 3b and an internal circuit 7 through the intermediaries of an external power source terminal 13 and an external earth terminal 14, but the degree of noise transferred is reduced by the impedance of a metal wire 17. As the external power source terminal 13 and the external earth terminal 14 are connected to the power source at a low impedance and a decoupling capacitor is generally connected between the terminals 13 and 14 in parallel, the source voltage noise and the earth voltage noise generating in an internal circuit 7 is very small.

Inventors

• 👤 Hiroshi Shinohara
• 👤 尋史 篠原
• 👤 Kenji Anami
• 👤 穴見　健治

Bibliographic Details