1、Lessons Learned Entry: 0297Lesson Info:a71 Lesson Number: 0297a71 Lesson Date: 1993-08-04a71 Submitting Organization: JPLa71 Submitted by: D. D. LordSubject: Integrated Circuit Damage due to Capacitor Residual Charge Abstract: When a discrete capacitor was installed in an electronic assembly, a resi
2、dual charge on the capacitor discharged through an integrated circuit itself and damaged the input circuit of the IC. Run tests to verify that procedures for the handling and storage of capacitors eliminate residual charges, and short capacitor leads just prior to installation.Description of Driving
3、 Event: Following installation of a discrete capacitor on an electronic assembly of a non-JPL project, an integrated circuit (IC) on that assembly was found to be inoperative. Further analysis indicated that the IC was damaged and that one of the chip inputs had likely been subjected to an excessive
4、ly high current (the IC damage was similar to that which results from an Electrostatic Discharge (ESD) condition).It was not clear whether or not the assembly procedures being followed included the use of established techniques designed to protect components from ESD. Additional review concluded, ho
5、wever, that the excessive current likely originated from a residual charge on the capacitor that had just been installed, and which was electrically connected to the IC input that failed.Laboratory tests were conducted and verified that, unless special precautions were taken, capacitors could accumu
6、late a residual charge, through normal handling and storage, that is sufficient to destroy an integrated circuit if allowed to discharge through one of its inputs. The conclusion was that the subject capacitor likely had a residual charge, and when it was electrically connected to the input of the I
7、C, it discharged through the IC itself and damaged the input circuit.Additional Keyword(s): Electronic Parts HandlingProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Reference(s): JPL IOM #523-WRW-91-390, W. R. Woods, Circuit Damage due to Assembly wi
8、th a Charged Capacitor.Lesson(s) Learned: 1. Capacitors can accumulate a residual charge, through normal handling and storage, sufficient to damage an integrated circuit.2. Assembly procedures may not adequately address the concern regarding the possibility of residual charges on capacitors, and the
9、 potential damage to integrated circuits.Recommendation(s): 1. Tests should be run to verify that procedures for the handling and storage of capacitors to be used in electronic assemblies result in the absence of capacitor residual charges.2. Assembly procedures should require the shorting of capaci
10、tor leads just prior to installation.3. Capacitor leads should be shorted from manufacturing through storage.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Energya71 Packaging Handling Storagea71 Parts Materia
11、ls & ProcessesAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 1993-08-26a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
