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White Paper ESCC Qualified SMD Fuse

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CHART F2 - PRODUCTION CONTROL CHART F3 - SCREENING TESTS

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

FuseFuse

Voltage drop Initial Measurementaccording to Paragraph 8.1.1.2 Burn-In (168h)according to Paragraph 8.3

Fig. 12: Parallel circuit of fuses

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

Applications

Solderabilityaccording to Paragraph 8.4

Satellites are very of- ten equipped with a multitude of electro- nic payloads, for a variety of functions, which are fed from a central supply unit. An example of this is the satellite communi- cation payload that is manufactured among other items by TESAT in Germany. This module amplifies the data signals that are transmitted via the antenna back to earth. The existence of numerous channels leads to a multiple redundant system. With an over-current caused by a fault in a channel, the fuse interrupts the supply in a secure and con- trolled manner. In a case such as this, the system switches over to another chan- nel. The disconnected fuse thus ensures that no unnecessary current flows in the defective channel.Should an application require a higher rated current than a single fuse can co- ver, a parallel switching (Fig. 12) of two or more fuses is possible. As a result of cur- rent/temperature equalisation between the fuses, simultaneous disconnection is ensured. It is to be noted that the fuses have to have the same rated current va- lues, that they are from the same produc-tion lot and individual voltage drop shall be within 2% for all fuses in parallel. In future, further R&D efforts will be made to increase current ratings by putting two or more fuses in parallel in one unit. This will also allow meeting the demand for higher current applications, since satellite technology gets more sophisti- cated and therefore power consumption will increase.Lucerne, 14

Current Carrying Capacity and Overload Operationaccording to Paragraph 8.5/8.6 Check for Lot Failureaccording to Paragraph 6.4 Delivery with Test Report Summary Flight Model, see ESCC QPL
th Approved according toESCC Generic Specifi cation no. 4008 + ESCC Detail Specifi cation no. 4008/001

June 2008

Fig. 10: Procedure for the screening process

produced. Every fuse undergoes a strict visual check so as to exclude material faults. Additional test fuses are manufactured with each production lot, which have also been subjected to Burn-In and relevant tests. Time- current cha- racteristics and soldera- bility tests are carried out to as- certain that these pro- perties are still fulfilled. Depending on custo-mer requirements fur- ther qualification tests can be carried out. As a result of this ex- tensive procedure, an absolute minimum failure rate is achie- ved as well as a com- plete guarantee of the electrical properties. Through the full qua- lification on the ESCC QPL, a test report summary is shipped with the products. At SCHURTER, retra- ceability of each sin- gle fuse back to the screening process is guaranteed. Thomas HubmannProduct Manager for Fuses SCHURTER AG Werkhofstrasse 8-12, 6002 LuzernTel. ++41 +41 369 33 60 Fax. ++41 +41 369 33 33thomas.hubmann@schurter.ch

Fig. 11: Burn-in equipment with fuses

Fuses

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