Patent ID: 6531744
Filing Date: 2003-03-11
Classification: H01L

Abstract:
Integrated circuit, comprising a substrate (SBSTR) with sub-circuits provided with a number of terminals, including a substrate terminal or earthing point (GND), a Vcc power supply terminal, an input point (in) and an output point (out), wherein at least one of the Vcc power supply terminal, the input point or the output point is connected via an overvoltage protection circuit to the substrate terminal or earthing point, wherein the overvoltage protection circuit comprises means with diode action formed in the substrate between the relevant terminal and the substrate terminal or earthing point, wherein the means comprise two or more diode elements of the Zener type connected in series, and the substrate of a first conductivity type is provided with a well (WLL) of a second, opposed conductivity type formed in the substrate and wherein a first diode element is provided in the substrate of the first conductivity type and is formed by a first pn junction between two surface areas (S1,S2) of opposed conductivity types arranged in the substrate, and at least one second diode element is provided in the well of the second conductivity type and is formed by a second pn junction between two surface areas (S3,S4) of opposed conductivity types arranged in the well and wherein the well insulates at least the second diode element from the first diode element, wherein an n+ surface area (S2,S4) of the pn junction is formed in a p+ surface area (S1,S3).