PURPOSE: To improve the electrostatic breakdown voltage of a line terminal by inserting a resistor into the source electrode side of a transistor.
CONSTITUTION: The part between drain electrode D and source electrode S is connected between line terminal 3 and earth terminal 4, and a resistor 5 is inserted to the source electrode S side of a transistor Q1 connecting a gate electrode G with the source electrodes S connection side of the line terminal 3 and earth terminal 4. Therefore, when overvoltage is applied to the line terminal 3 by this resistor 5, it is possible to reduce electric current flowing between the drain electrode D and source electrode S of the transistor Q1. Thus, the strength against overvoltage of the transistor Q1 constituting a protection network can be improved so that the electrostatic breakdown voltage of the line terminal 3 is improved too.
KAWAHARA TAKU
GOHO YASUSHI
OKADA MASAYA
