Patent ID: 6768616
Filing Date: 2004-07-27
Classification: H01L,H03K

Abstract:
An electrostatic discharge (ESD) protection circuit in a semiconductor integrated circuit (IC) having protected circuitry, the ESD protection circuit comprising:a pad, adapted for connection to a protected circuit node of the IC; a silicon controlled rectifier (SCR) having a P-type anode formed in an N-well bulk region, said anode coupled to the pad, and an N-type cathode formed in a P-well bulk region, said cathode coupled to ground; and at least one series PN junction diode, each series diode having an anode and a cathode respectively coupled in a forward conduction direction from a second gate of the SCR to ground, wherein the P-type anode and the N-well bulk region of said SCR form a second PN junction diode, said second PN junction diode being serially coupled in a forward direction with said at least one series PN junction diode.