Chip fuse is pulse and temperature resistant Professionalمنذ 4 أشهر - Multimedia - Salah Bey - 69 الآراء
In consumer applications where low rated currents and breaking capacities are required, Chip Fuses are emerging to satisfy designers’ demands for the next level of component miniaturization.
Chip fuses feature a conductive fuse element that is typically deposited as a thick-film, electroplated, or thin-film layer onto a ceramic substrate. Using these basic technologies, secondary over-current protection is able to migrate into smaller SMT packages including 1206, 0603, and even 0402. However, two further imperatives are the need for long-term stability of the fusing characteristic and a low unit price to enable a cost-effective solution. Stability is heavily dependent on the accuracy of the fabrication technique used to create the fuse element. Traditionally, a thick-film element for a chip fuse is deposited using a screen printing process, while most fuse elements are electroplated. Both of these techniques enable quite accurate control over the dimensions of the fuse element in order to achieve the desired fusing characteristic. However, the homogeneous crystal structure of the metal layer has an important influence over the long-term stability, due to aging factors such as power dissipation or external high temperatures in combination with thermal cycles. To simultaneously improve control over the dimensions and crystal structure of the fuse element, Vishay Beyschlag MFU-series chip fuses are created using a thin film sputtering process in place of screen printing or electro-plating.
This process leverages precision chip resistor manufacturing knowledge and assembly capacity. In addition, a special protective coating comprising layers of glass and epoxy lacquer also now raises the capability of chip fuses to withstand harsh thermal shocks and wide-ranging humidity requirements. Benchmark tests on MFU series chip fuses demonstrate superior performance in this respect due to this special protective system.
The thermally activated fuse is the oldest circuit protection device and is still in widespread use. It is well understood, reliable, consistent, and approved by regulatory standards. However, with end products increasing in complexity and shrinking in size, designers need an alternative to the user-replaceable fuse and fuse holder in order to reduce the form factor, simplify assembly, improve ruggedness, and further enhance safety.
Instead, designers can use surface mount devices (SMDs) without a performance compromise. SMD- Mount Fuses employ diverse technologies to provide thermal-based fusing along with the full range of necessary fuse characteristics, such as fast acting and slow blow.