Patent ID: 8860082

Claim:
A transient voltage suppressor (TVS) circuit for coupling to a protected circuit to limit amplitude of a transient voltage which is inputted to the protected circuit, the TVS circuit comprising: a suppressor device, which has a PN junction for limiting amplitude of the transient voltage; and at least one diode device, which is coupled between the protected circuit and the suppressor device, wherein the diode device has a PN junction which is coupled to the PN junction of the suppressor device in a reverse direction; wherein the diode device is formed in a P-type substrate, which has an upper surface, the diode device including: an N-type well, which is formed in the substrate beneath the upper surface; a separation region, which is formed in the substrate beneath the upper surface, wherein the separation region is located in the well from top view; a P-type anode region, which is formed beneath the upper surface at one side of the separation region; an N-type cathode region, which is formed beneath the upper surface at the other side of the separation region, wherein the cathode region is separated from the anode region by the separation region; and an N-type buried layer, which is formed in the substrate below the well, wherein the buried layer has an impurity concentration higher than that of the well.