Patent ID: 8482373

Claim:
An over-current protection device having opposite upper and lower surfaces and four planar lateral surfaces interconnecting the upper and lower surfaces, each of two adjacent ones of the four planar lateral surfaces defining a corner; the over-current protection device comprising: a PTC material layer having opposite first and second surfaces; a first conductive layer in physical contact with the first surface of the PTC material layer; a second conductive layer in physical contact with the second surface of the PTC material layer; a first electrode comprising a pair of first metal foils at the upper and lower surfaces, and being electrically connected to the first conductive layer and electrically isolated from the second conductive layer; a second electrode comprising a pair of second metal foils at the upper and lower surfaces, and being electrically connected to the second conductive layer and electrically isolated from the first conductive layer; and four conductive vias each formed at the corner of two adjacent planar lateral surfaces, wherein two conductive vias connect the pair of the first metal foils and the first conductive layer, and the other two conductive vias connect the pair of the second metal foils and the second conductive layer; the sum of cross-sectional areas of the four conductive vias is around 7%-20% of a form factor area of the over-current protection device.