ESD PROTECTION CIRCUIT

摘要

PURPOSE: An ESD(Electro Static Discharge) protection circuit is provided to improve the reliability of an ESD protection circuit by connecting a part of a VSSQ with a VSS of other inner circuit. CONSTITUTION: A drain of a PMOS transistor(33) is connected with a pad(31). A gate of the PMOS transistor(33) is connected with a main chip(32). A source of the PMOS transistor(33) is connected with a VCC. A drain of the first NMOS transistor(34) is connected with the pad(31). A source of the first NMOS transistor(34) is connected with a VSSQ. A gate of the first NMOS transistor(34) is connected with the main chip(32). A drain of the second NMOS transistor(35) is connected with the pad(31). A source and a gate of the second NMOS transistor(35) are connected with the VSSQ. A drain of the third NMOS transistor(36) is connected with the pad(31). A source and a gate of the third NMOS transistor(36) are connected with the VSS.