我做过的几个项目ESD解决问题的方法

Case1．S888－/S888ESDproblemimprovementForS888-V00,therearesomeESDproblemsasfollow,1.Themobilewilllosecommunicationandsearchnetworkagainwhendischargingtoarrowkeyanddatakeyatair6KVincommunicationstate,2.Themobilewilllosecommunicationandsearchnetworkagainwhendischargingtosidekeyandcameradecorationringatair5KVincommunicationstatewithmobiledownwards,3.Themobilewillpowerofforlostnetworkwhenreleasingstaticfromtheheadsetspeakeratair5KVinmobilewithheadsetstate.4.ThePAwilldestroywhendischargingtothecameradecorationringatair5KV.Fortheseproblems,thesolutionsareasfollow,Problem1improvement:MakethemetaldomeandMMIGNDwellconnectedwithtwopoints,andkeeptheresistancebetweenmetaldomeandtheGNDunder2ohm,Afterimprovement,itisOKforESDatair10KVonthearrowkeyanddatakey.Problem2improvement:(1)ScratchtheNBSCANtestpointwhichisjustunderthemetaldome.(2)Adda10nfcapacitorontheNBSCANtestpoint.(3)Changetheformersparsemetaldomewithdensemetaldome.Afterimprovement,itisOKforESDatair10KVonthepositionofsidekeyandcameradecorationring.Problem3improvement:(1)AddTVSESDAVLC6V1-1M2ontheHSGND,itisOKforESDatair10KV.(2)Add10nfcapacitorontheHSGND,itisOKforESDatair10KV.Afterimprovement,itisOKforESDatair10KVwhenreleasingstaticfromtheheadsetspeaker.Problem4improvement:UseisolatedtapetocovertheantennawhichisnearthegapofthecameradecorationringAfterimprovement,itisOKforESDatair10KVwhendischargingtothecameradecorationring.1.1.KEYPADPROBLEMDescriptionWhendischargingtoarrowkeyanddatakeyatair6KVincommunicationstate,themobilewilllosecommunicationandsearchnetworkagain.ProblemanalysisAtfirstthemetaldomeisconnectedwiththeGNDbyonepointandtheresistancebetweenthemetaldomeandtheGNDisbiggerthan2ohm,whendischargingtoarrowkeyanddatakeyatair7KVincommunicationstatus,themobilewilllosenetworkandsearchnetworkagain.ImprovementWhenkeeptheresistancebetweenmetaldomeandtheGNDunder2ohm,itwillnotlosenetworkagainatair10KV,soitisadvisedtokeepthemetaldomeconnectedwiththeGNDbytwopointandkeeptheresistancebetweenthemunder2ohm.Afterimprovement,itisOKforESDatair10KVonthearrowkeyanddatakey.1.2.SIDEKEYANDCAMERADECORATIONRINGPROBLEMDescriptionWhendischargingtosidekeyandcameradecorationringatair5KVincommunicationstatewithmobiledownwards,themobilewilllosecommunicationandsearchnetworkagain.ProblemanalysisAstheNBSCANtestpointisjustunderthemetaldomeandverysensitivetoESD,whenmobiledownwards,theNBSCANtestpointiseasilyaffectedbycouplingelectricfieldformedbetweenworkbenchandtheMMI.WhendischargingtosidekeyandcameradecorationringatOnlyonepointformetaldometoconnectwithGND,theresistancebetweenmetaldomeandGNDisbiggerthan2ohmUsetwopointstomakemetaldomeconnectwiththeGNDwellandkeeptheresistancebetweenthemunder2ohm.air5KVincommunicationstatewithmobiledownwards,themobilewilllosecommunicationandsearchnetworkagain.Improvement(1)ScratchtheNBSCANtestpointwhichisjustunderthemetaldome,itisOKforESDatair10KVonthepositionofsidekeyandcameradecorationring(2)Adda10nfcapacitorontheNBSCANtestpoint,itisOKforESDatair10KVonthepositionofsidekeyandcameradecorationring(3)Changetheformersparsemetaldomewithdensemetaldome,itisOKforESDatair10KVonthepositionofsidekeyandcameradecorationring.1.3.RELEASINGSTATICPROBLEMDescriptionTheNBSCANtestpointisverysensitivetoESD.SparsemetaldomeDensemetaldomeChangetheformersparsemetaldomewithdensemetaldomeThemobilewillpowerofforlostnetworkwhenreleasingstaticfromtheheadsetspeakeratair5KVinmobilewithheadsetstate.ProblemanalysisAstheC50110nfcapacitorontheHSGNDisnotmounted,whenreleasingstaticfromtheheadsetspeaker,themobilewillpowerofforlostnetwork.Improvement(1)AddTVSESDAVLC6V1-1M2ontheHSGND,itisOKforESDatair10KV.(2)Add10nfcapacitorontheHSGND,itisOKforESDatair10KV.Afterimprovement,itisOKforESDatair10KVwhenreleasingstaticfromtheheadsetspeaker.1.4.PADESTROYPROBLEMDescriptionThePAwilldestroywhendischargingtothecameradecorationringatair5KV.ProblemanalysisAsantennaisverynearfromthecameradecorationring,whendischargingtothegapofthering,ESDwilleasilyreleasetotheantennaanddestroythePA.ImprovementWhenuseisolatedtapetocovertheantenna,itwillpreventESDdirectlyreleasetotheantenna,andthenitcanprotectthePAfrombeingdamagedbyESD.AsNMC501,whenreleasingstaticfromtheheadsetspeaker,themobilewillpowerofforlostnetwork.AntennaisverynearfromthecameradecorationringandcanbeeasilydischargedbyESDdirectlyAfterimprovement,itisOKforESDatair10KVwhendischargingtothecameradecorationring.Case2．DX2007B1ESDproblemimprovementDuringqualification,therearesomeESDproblems,1.TherewillbepoweroffwhendischargingtoI/Oconnectoratcontact3.5KV,2.TherewillbepoweroffwhendischargingtoT-flashconnectoratair7KV,3.Therewillbecommunicationlostandcan’treadSIMcardwhendischargingtokeypad,T-flashconnectorandgapatair7KV.Fortheseproblems,thesolutionsareasfollow,Problem1improvement:IncreasetheGNDareaofthebattery’scathodebyscrapingthegreenpaintingnearthecathodetoexposemoreGNDandlinkingthecathodewiththeexposedGNDbysolder.Afterimprovement,itisOKforESDatcontact6KVontheI/Oconnector.Problem2improvement:LinkthemetalpanelofthebackcoverwiththeSIMcardshieldingcoverby