EN/LZT146049R4A EricssonPowerModules,March2007
PMB4518TWPDatasheet
EricssonPowerModulesDC/DCconvertersandDC/DCregulators
aredesignedinaccordancewithsafetystandards
IEC/EN/UL60950, Safety of Information Technology Equipment.
IEC/EN/UL60950containsrequirementstopreventinjuryor
damageduetothefollowinghazards:
Electrical shock
Energy hazards
Fire
Mechanical and heat hazards
Radiation hazards
Chemical hazards
On-boardDC-DCconvertersaredefinedascomponentpower
supplies.Ascomponentstheycannotfullycomplywiththe
provisionsofanySafetyrequirementswithout“Conditionsof
Acceptability”.Itistheresponsibilityoftheinstallertoensurethat
thefinalproducthousingthesecomponentscomplieswiththe
requirementsofallapplicableSafetystandardsandDirectivesfor
thefinalproduct.
Componentpowersuppliesforgeneraluseshouldcomplywith
therequirementsinIEC60950,EN60950andUL60950“Safetyof
informationtechnologyequipment”.
Thereareothermoreproductrelatedstandards,e.g.
IEC61204-7“Safetystandardforpowersupplies",
IEEE802.3af“EthernetLAN/MANDataterminalequipment
power”,andETS300132-2“Powersupplyinterfaceattheinput
totelecommunicationsequipment;part2:DC”,butallofthese
standardsarebasedonIEC/EN/UL60950withregardstosafety.
EricssonPowerModulesDC/DCconvertersandDC/DCregulators
areUL60950recognizedandcertifiedinaccordancewithEN60
950.
Theflammabilityratingforallconstructionpartsoftheproducts
meetsUL94V-0.
Theproductsshouldbeinstalledintheend-useequipment,in
accordancewiththerequirementsoftheultimateapplication.
NormallytheoutputoftheDC/DCconverterisconsideredasSELV
(SafetyExtraLowVoltage)andtheinputsourcemustbeisolatedby
minimumDoubleorReinforcedInsulationfromtheprimarycircuit
(ACmains)inaccordancewithIEC/EN/UL60950.
Safety Specification
IsolatedDC/DCconverters.
TheinputvoltagetotheDC/DCregulatorisSELV(SafetyExtraLow
Voltage)andtheoutputremainsSELVundernormalandabnormal
operatingconditions.
Itisrecommendedthataslowblowfusewitharating
twicethemaximuminputcurrentperselectedproduct
beusedattheinputofeachDC/DCregulator.
Non-isolatedDC/DCregulators.
24Vdcsystems.
TheinputvoltagetotheDC/DCconverterisSELV(SafetyExtraLow
Voltage)andtheoutputremainsSELVundernormalandabnormal
operatingconditions.
48and60Vdcsystems.
IftheinputvoltagetoEricssonPowerModulesDC/DCconverter
is75Vdcorless,thentheoutputremainsSELV(SafetyExtraLow
Voltage)undernormalandabnormaloperatingconditions.
Singlefaulttestingintheinputpowersupplycircuitshouldbe
performedwiththeDC/DCconverterconnectedtodemonstrate
thattheinputvoltagedoesnotexceed75Vdc.
IftheinputpowersourcecircuitisaDCpowersystem,thesource
maybetreatedasaTNV2circuitandtestinghasdemonstrated
compliancewithSELVlimitsandisolationrequirementsequivalent
toBasicInsulationinaccordancewithIEC/EN/UL60950.
Itisrecommendedthatafastblowfusewitharating
twicethemaximuminputcurrentperselectedproduct
beusedattheinputofeachDC/DCconverter.Ifaninputfilteris
usedinthecircuitthefuseshouldbeplacedinfrontoftheinput
filter.
Intherareeventofacomponentproblemintheinputfilterorinthe
DC/DCconverterthatimposesashortcircuitontheinputsource,
thisfusewillprovidethefollowingfunctions:
IsolatethefaultyDC/DCconverterfromtheinputpowersource
soasnottoaffecttheoperationofotherpartsofthesystem.
Protectthedistributionwiringfromexcessivecurrentandpower
lossthuspreventinghazardousoverheating.
Thegalvanicisolationisverifiedinanelectricstrengthtest.Thetest
voltage(VISO)betweeninputandoutputis1500Vdcor2250Vdcfor
60seconds(refertoproductspecification).Leakagecurrentisless
than1Aatnominalinputvoltage.
Generalinformation.