Patent ID: 8049250

Claim:
An ESD protection structure, comprising: a semiconductor substrate of a first conductivity type; a first well of the first conductivity type formed into the semiconductor substrate; a second well of a second conductivity type formed into the semiconductor substrate adjacent to the first well, the intersection of the first and second wells forming a p-n junction; a first diffused region of the first conductivity type formed at the surface of the first well and electrically coupled to a ground supply terminal; a first pad contact region of the second conductivity type formed at the surface of the first well, separated from and proximal to the first diffused region by an isolation region formed in the first well, and the first pad contact region electrically coupled to a pad terminal; a second diffused region of the second conductivity type formed at the surface of the first well separated from and proximal to the pad contact region of the second conductivity type and electrically coupled to the ground supply terminal; a third diffused region of the first conductivity type formed in the surface of the second well and electrically isolated from and proximate to the second diffused region, the electrical isolation performed by an isolation region formed in the second well, and the third diffused region electrically coupled to a positive power supply terminal; a second pad contact region of the first conductivity type formed at the surface of the second well and electrically isolated from and proximate to the third diffused region, the electrical isolation performed by a second isolation region formed in the second well, and the second pad contact electrically coupled to the pad terminal; a fourth diffused region of the second conductivity type formed at the surface of the second well and electrically isolated from and proximate to the second pad contact region, the electrical isolation performed by a third isolation region formed in the second well, and the fourth diffused region electrically coupled to the positive supply terminal; and an RC power clamp circuit coupled between the positive supply terminal and the ground supply terminal and configured to trigger the ESD protection by coupling the RC power clamp circuit to the first and second wells.