Fuses for over-current circuit protection have been used in space applications for a con-siderable period of time. With the MGA-S and as a manufac- turer of passive components, SCHURTER is not only able to provide a fuse product, which meets all requirements for this industry but is also qualified ac-cording to ESCC Generic Spe-cification no. 4008. As a listed supplier at ESCC and as a Euro- pean fuse supplier, SCHURTER offers a product that is made using thin-film technology. The standard version for industrial applications has been on the market since 1990 and has annual sales of more than one million pieces. This clearly demonstrates a stable manufacturing process toge-ther with operation at a high quality level. For the space version, where only narrow tolerances in the manufacturing process are accepted, eight thousands fuses have been manufactured and passed through the screening procedure. The customer TESAT in Germany has reported no fai- lures to date. This article gives an insight into the fuses technical data, its design, manufacturing process and application information. > For its type (Fig. 1) the fuse is very small (3.2 x 1.55 x 1.55 mm or a 1206 footprint) and is intended for use in both direct (DC) and alternating (AC) current circuits. They are capable of operation in an ambient temperature range of -55 ҰC to 150 C including high vacuum environments (< 50 mTorr).Е The current range extends from 140 mA to 3.5 A for continuous operation. Based on the rated current, the re- commended derating curve is shown (Fig.2). The fuse can be operated at its rated current indefinitely, this being in accor-dance with the IEC definition of rated current. In contrast, one of the require- ment of UL 248-14 is that a fuse must operate at its rated current (1.0 x In) for at least four hours. After this time, the fuse should be able to open and disconnect the circuit. This means, therefore, that a UL type fuse should not be operated continuously above 75% of its rated current. The previous de- finition of the current ran- ge which is > Fig. 1: MGA-S Fuse

The finished single fuses are put in a chamber (Fig. 8) called a bomb˻ where with high pressure and an acid solvent tests whether the fuses are sealed. The test lasts 72 hours with cyclic tests up to 1500 PSI.The conditioning process lasts a total of 84 hours and the temperature is increa- sed to 150 ˚C. This ensures that the acid solvent shows those fuses that have not been sealed and where the electrical cha- racteristic of the fuse has changed. The- se can be then be separated out with a cold resistance measurement. The fuses are only placed into stock if the test has shown them to be sealed....

External Visiual Inspectionaccording to Paragraph 5.2.1 Dimension Checkaccording to Paragraph 5.2.2 Cold Resistance Initial Measurementaccording to Paragraph 5.2.1 Current Carrying Capacity and Overload Operation Testaccording to Paragraph 5.2.4/5.2.5 > Voltage drop Initial Measurementaccording to Paragraph 8.1.1.2 Burn-In (168h)according to Paragraph 8.3 > Voltage drop Final Measurementaccording to Paragraph 8.1.1.2 External Visual Inspection according to Paragraph 8.2Cold Resistance Final Measurementaccording to Paragraph 8.1.1.1Test Equipment for Burn-In > Current Carrying Capacity and Overload...