Patent ID: 7408754

Claim:
An ESD device, comprising: a PNP bipolar transistor and a NPN bipolar transistor connected with each other to form a silicon-controlled rectifier (SCR); a first trigger device coupled between an emitter of the PNP bipolar transistor and a base of the NPN bipolar transistor, the first trigger device comprising at least one NMOS pass gate having a source and a drain formed in a first floating well in a semiconductor substrate with a gate coupled to the drain and the source coupled to the first floating well; a second trigger device coupled between a base of the PNP bipolar transistor and an emitter of the NPN bipolar transistor, the second trigger device comprising at least one NMOS pass gate having a source and a drain formed in a second floating well in the semiconductor substrate with a gate coupled to the drain and the source coupled to the second floating well; a first external resistor coupled between the base and emitter of the NPN bipolar transistor; and a second external resistor coupled between the base and emitter of the PNP bipolar transistor; wherein the base of the NPN bipolar transistor is a third floating well formed in the semiconductor substrate; and wherein said PNP bipolar transistor and said NPN bipolar transistor turn on simultaneously in response to an ESD pulse on the ESD device.