Input protection circuit connected to protection circuit power source potential line

摘要

An input protection circuit capable of precisely bypassing a surge current to a power source terminal and protecting the gate of a protective transistor from an electrostatic surge. The input protection circuit has an input terminal which receives an input signal, a first power source terminal which receives a first power source electric potential, and a first protective power source potential line connected to the first power source terminal for supplying the first power source electric potential to an input protection circuit. The input protection circuit has a first input protection transistor of a first conductive type having a drain connected to the input terminal, a gate and a source connected to the first protective power source potential line. Moreover, the input protection circuit has a second input protection transistor of the first conductive type having a drain connected to an input terminal of an internal circuit, a gate connected to the input terminal via a protective resistor, and a source connected to the first protective power source potential line.