Input/output protection circuit having an SOI structure

摘要

An I/O protection circuit includes a P-channel MOS transistor connected between an input terminal and a power supply line, and an N-channel MOS transistor connected between the input terminal and a ground line. Gate electrodes of both the transistors are floated. The transistors may be replaced with gate diodes. Further, gate electrodes may be formed from the same layer as a gate electrode provided for field shielding.