Semiconductor device including electrostatic protection circuit

Abstract

A semiconductor device includes: a first power source (PS 1 ) pad supplied with a PS 1 voltage; a PS 1 line connected to the PS 1 pad; a first ground line (G 1 ); an output circuit operated using the PS 1 voltage; a second power source (PS 2 ) pad supplied with a PS 2 voltage; a PS 2 line connected to the PS 2 pad; a second ground line (G 2 ); a signal line connected to an output end of the output circuit; an input circuit connected to the signal line at an input end receiving a signal from the output end and operated using the PS 2 voltage; a main protection circuit unit providing discharge routes between the PS 1 pad and G 1 , G 1 and G 2 , and G 2 and the PS 2 pad; and a sub protection circuit unit. The output circuit includes: a circuit element arranged between the PS 1 line and the signal line and able to function as a resistive element.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 a first power source pad to which a first power source line is connected;   a second power source pad to which a second power source line is connected;   a first circuit coupled with the first power source line; and   a second circuit coupled with the second power source line, and coupled with the first circuit via a signal line,   wherein a first voltage is supplied to the first power source line through the first power source pad,   wherein a second voltage different from the first voltage is supplied to the second power source line through the second power source pad, and   wherein a first transistor is coupled with the signal line.   
     
     
         2 . The semiconductor device according to  claim 1 ,
 wherein the first transistor is coupled with the signal line through a diode.   
     
     
         3 . The semiconductor device according to  claim 1 ,
 wherein the first transistor is coupled with the signal line through a resistor.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein the first transistor is coupled with the signal line through a second transistor.