Miniaturization of circuit protection devices to meet surface mount applications

The electronic industry´s trend toward surface mount technology is influencing the fabrication methodology of all components including circuit protection devices. Conventional circuit protection devices such as fuses are typically constructed of wire filaments as the fusible link. However, the packaging constraints of surface mount components makes it extremely difficult to handle small filament wires in a cost effective manner. The fabrication of fuses and the packaging of the components has demanded that fuse designers and manufacturers consider other technologies for the construction of these devices. For surface mount fuses configured in a “1206” package size, these technologies include electroless copper thin film deposition, sputtered aluminum thin film deposition, and gold wire bond processing. This paper discusses these fabrication technologies and address a comparison of the attributes, both physical and electrical, of these technologies as viable fusible links for various surface mount fuse constructions