Patent ID: 9111752
Filing Date: 2015-08-18
Classification: H01L

Abstract:
1. An electrostatic discharge protection device, comprising: a P-type substrate set as floating; a common N-well formed in the P-type substrate; a common N-doped region formed in the first common N-well, wherein the common N-doped region is electrically connected to a reference voltage node; a common P-doped region formed in the common N-well, wherein the common P-doped region surrounds the common N-doped region, the common P-doped region and the common N-well form a common diode; a plurality of peripheral N-wells formed in the P-type substrate and surrounding the common N-well, each of the peripheral N-wells comprising a P-type doped region and a N-type doped region, wherein the P-type doped region is electrically connected to one of a plurality of I/O terminals; and a circular P-doped region formed in the P-type substrate and disposed between the common N-well and the peripheral N-wells, and the circular P-doped region surrounding the common N-well; wherein the common P-doped region, the circular P-doped region, and the N-type doped region are electrically connected to a bus.