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1、PreparedBy:Ivan.Zhang3GProductsC33,C34BurntIssue3G产品C33,C34炸机问题Index索引Failurehistory失效历史Problemdescription问题描述Failureanalysis失效分析Designexperiment设计实验ConclusionandCA结论和改善措施ProblemDescription问题描述Background背景TheC33andC34failureratesuddenlytoriseinJan.2009andcausedtheproductionlinetoshutdown.MRBmeeti
2、ngheldtodiscusstheshorttermandlongtermcorrectiveactionandplantwithstoodbigshippingpressureaccordingly.2009年11月份3G产品C33,C34不良率大幅上升,产线因此停线。工厂召开MRB会议讨论对策,出货压力骤升。Pic.13GProductsProblemDescription问题描述Symptom症状ThefailedunitswiththesymptomthatC33,C34,Q10,Q11burntatfirstACstartup.TheunitscanpassallATEtes
3、titemafterreplacingtheC33,C34,Q10,Q11.不良机器在Runup第一个测试项目---ACstartUP项起机瞬间便炸C33,C34,Q10,Q11同时击穿。更换C33,C34,Q10,Q11后机器可以通过所有ATE测试。FailureHistory失效历史TherepairrecordshowsthefailurecantracebacktoJan.2009,itmeanssuchfailureexistedfromthebeginningof3GproductsbuildinSTJplant.Thefailurerateisabout974ppm.维修记
4、录显示失效状况可以追溯到2009年1月,也就说这种失效从3G产品在STJ工厂生产就存在着。失效率大约为974ppm。.CauseAndEffectDiagram特性要因图C33,C34burntMechanicalDamageComponentSMTProcessDesign/ApplicationTestProcessOthersPossibleCauseDescriptionandhintsDesign/ApplicationSuspectthereisdesignmarginalorapplicationissueonthePSU.ComponentSuspectcomponent
5、swithsomethingwrongSMTProcessNoabnormalitywasfoundonSMT.MechanicalDamageSuspectmechanicaldamage.TestProcessNoabnormitywasfound.OthersNoabnormitywasfound.ApplicationAnalysis应用分析Circuitanalysis电路分析Sch.1RelatedschematicdiagramApplicationAnalysis应用分析Waveform.1ACline:186V,loading:0AWaveform.4ACline:23
6、0V,loading:33AWaveform.3ACline:230V,loading:0AWaveform.2ACline:186V,loading:33AApplicationAnalysis应用分析Waveform.5ACline:264V,loading:0AWaveform.6ACline:264V,loading:33AWaveformdescription:CH1:C33Voltage;CH2:C34Voltage.C33,C34workasthesnubbercapacitorofQ10andQ11,inthishalf-bridgetopology,theC33andC
7、34arechargedjustwhentheAClineturnedon,whentheQ10ison,theQ11isoff,theC33dischargesatthesametime;SoandC34,Q11.ApplicationAnalysis应用分析以上波形中,CH1:C33电压波形;CH2:C34电压波形。C33,C34作为缓冲电容保护Q10,Q11,在此半桥拓扑中,我们从上面的波形可以看到,加市电瞬间,C33,C34