Wednesday, 27 January 2016

Precision and low power consumption: SMD fuses from SCHURTER

The range of battery-powered devices extends from powerful hand tools for craftsmen, to sensors for room surveillance all the way through to life-saving medical aids. The safety of such devices presents quite a challenge. To ensure the safe operation of standalone devices, SCHURTER offers two SMD fuses with low power dissipation and tight tolerances for tripping time.

Many types of damage can be avoided with effective overcurrent protection. In principle, a fuse is sufficient for this purpose. Although unimposing, a fuse must meet a wide range of challenging requirements, if it is to provide for the efficient and effective safe operation of insulin pumps, hearing aids or blood glucose meters. In principle, overcurrent protection can also be implemented with an active protection circuitry. The SMD fuses from SCHURTER, however, can replace such an approach with distinct advantages.

A fuse is clearly more reliable compared to an active protection circuitry. In addition, it requires little space at low cost. In terms of power dissipation and tripping time, there is a clear difference among the various fuses available on the market. As for all these aspects, both the USF 0402 and USFF 1206 SMD fuses from SCHURTER feature values that make them a perfect solution for overcurrent protection in battery-driven devices. Both fuses have been developed for the overcurrent protection of secondary circuits.

The first characteristic that differentiates these units from standard commercial products is their low power dissipation. This is made possible by a unique design. The melting wire is wire-bonded and it is just a few micrometers thick. It is made of a special metal alloy. In the case of the USF 0402, the melting wire is encapsulated in a special epoxy resin; on the USFF 1206, which is somewhat larger, it is surrounded by air. Both technologies inhibit the dissipation of heat and thus drop power dissipation.

The second differentiating characteristic is their tight tolerance in tripping time. With a nominal tripping time of 0.5 milliseconds, for instance, the fuse trips within a tolerance band between 0.4 and 0.6 milliseconds. The USF 0402 and USFF 1206 are currently the only fuses in this dimension that trip with such high precision. This precise tripping time increases safety for users, the environment and the device itself. Both SMD fuses make it possible to design standalone devices without active protection circuitry, which has a positive impact on the cost, size and battery lifetime of the corresponding device.

In past years, SCHURTER has continually enhanced its know-how and applied it to both of these unique fuses. The company is delighted to be able to support its customers with this knowledge. Furthermore, custom-designed solutions are also possible such as versions of both fuses with current ratings outside the E Series. 

You can find a detailed product overview of all Schurter SMD fuse products on our website.
Download the whitepaper.