Input clamping circuit

Abstract

Abstract PURPOSE:To accomplish sufficient protection of the internal circuits against excessive input level by arranging a static breakdown checking element and an input clamping transistor in a circuit in such a manner that the emitter of the transistor is connected to the input terminal and the internal circuits while the collector thereof to the power source. CONSTITUTION:A clamping circuit is provided with a bonding pad BP, an n<+>- type diffused resistances 11 and 12, a static breakdown checking element 13 composed of a horizontal npn-transistor made up of an n<+>-type diffused region and a p-type semiconductor substrate and the like. It is also provided with a ground 14, a terminal 17 connected to the internal circuits, and an input clamping transistor 18 composed of a horizontal npn transistor made up of an n<+>-type diffused region and a substrate, a power supply terminal 19 and the like. With such an arrangement, the emitter of the transistor 18 is connected to the terminal 17 through a contact section ct while the collector thereof to the terminal 19 through the contact ct. Excessive input, if any, can be clamped while s small number of carrier dhecked from injection to the substrate.

Inventors

• 👤 Takumi Miyashita
• 👤 Koichi Mikome
• 👤 Joji Murakami
• 👤 Yoshio Watabe
• 👤 Takashi Matsui

Bibliographic Details