Patent ID: 7719026

Claim:
A protective device comprising: an N-Well ( 12 ) and an adjoining P-Well ( 30 ); a first p-type structure ( 14 ) formed in the N-Well, the first p-type structure providing an emitter, the N-Well a base and the P-Well a collector of a PNP bipolar transistor, wherein the emitter and the base together form an anode of the protective device; a first n-type structure ( 26 ) formed in the P-Well, the first n-type structure providing an emitter, the P-Well a base and the N-Well a collector of an NPN bipolar transistor, wherein the emitter and the base together form a cathode of the protective device; an ESD structure ( 18 ) formed bridging the N-Well and the P-Well, the ESD structure having a higher n-type doping density than the N-Well; a PLDD structure ( 21 ) formed in the P-Well at a lateral distance, L 1 , from the ESD structure ( 18 ), the PLDD structure having a doping level higher than the P-Well; an N+ structure ( 16 ) formed in the ESD structure, the N+ structure ( 16 ) having a higher n-type doping density than the ESD structure ( 18 ); a P+ structure ( 20 ) formed in the PLDD structure, the P+ structure ( 20 ) having a higher doping density than the PLDD structure, wherein an edge of the N+ structure ( 16 ) is at a lateral distance LX from the nearest edge of the P+ structure ( 20 ); wherein the difference between L 1 and LX determines, in part, the breakdown voltage and the holding voltage of the protective device.