Patent ID: 7061052

Claim:
An input protection circuit comprising: an input terminal which receives an input signal; a first power source terminal which receives a first power source electric potential; a second power source terminal which receives a second power source electric potential; a first power source line connected to said first power source terminal; a second power source line connected to said second power source terminal; a first input protective transistor of a first conductive type having a drain, a gate and a source, said drain being connected to said input terminal, and said gate and said source being connected to said first power source line; a second input protective transistor of a second conductive type having a drain, a gate and a source, said drain being connected to said input terminal, and said gate and said source being connected to said second power source line; and an inverter including a first transistor and a second transistor, said first transistor having a drain, a gate and a source, said drain being connected to an internal circuit, said gate being connected to the input terminal via a protective resistor, and said source being connected to said first power source line, and said second transistor having a drain, a gate and a source, said drain being connected to the internal circuit, said gate being connected to the input terminal via the protective resistor, and said source being connected to said second power source line, wherein the source of the first input protective transistor and the source of the first transistor of the inverter are formed in a common region in a first conductive type impurity active region.