DC/DC regulator Input 3.0 - 5.5 V Output 16 A

Key Features • Wideinput,3.0-5.5Vdc

• Programmableoutput,0.75-3.6Vdc

• Undervoltageprotection

• Shortcircuitprotection

• Remotesense

• RemoteOn/Off

• DesignforEnvironment(DfE)

• EuropeanCommissionDirective2011/65/EU(RoHs)compliant

Datasheet

DC/DCregulatorInput3.0-5.5VOutput16A

PMB4518TWP

ThePMBseriesofSILDC/DCregulators(POL)areintendedtobeusedaslocaldistributedpowersourcesindistributedpowerarchitec-turelevel4.Thesinglein-linedesignmakesthePMBseriessuitableforapplicationswhereboardspaceislimited.ThehighefficiencyandhighreliabilityofthePMBseriesmakesthemparticularlysuitedforthecommunicationsequipmentoftodayandtomorrow.

Theseproductsaremanufacturedusingthemostadvancedtechnologiesandmaterialstocom-plywithenvironmentalrequirements.Designedtomeethighreliabilityrequirementsofsystemsmanufacturers,thePMBrespondstoworld-classspecifications.

FlexisanISO9001/14001certifiedsupplier.

ContentsProductProgram. . . . . . . . . . . . . . . . . . . . . . 2MechanicalData. . . . . . . . . . . . . . . . . . . . . . 2Connections . . . . . . . . . . . . . . . . . . . . . . . . . 2AbsoluteMaximumRatings . . . . . . . . . . . . . 3Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3ProductQualificationSpecification. . . . . . . . 4SafetySpecification . . . . . . . . . . . . . . . . . . . 5Adjustedto1.0Vout-Data. . . . . . . . . . . . . 6Adjustedto1.2Vout-Data. . . . . . . . . . . . . 9Adjustedto1.5Vout-Data. . . . . . . . . . . . 12Adjustedto1.8Vout-Data. . . . . . . . . . . . 15Adjustedto2.5Vout-Data. . . . . . . . . . . . 18Adjustedto3.3Vout-Data. . . . . . . . . . . . 21EMCSpecification. . . . . . . . . . . . . . . . . . . . 24OperatingInformation. . . . . . . . . . . . . . . . . 24ThermalConsiderations . . . . . . . . . . . . . . . 27SolderingInformation. . . . . . . . . . . . . . . . . 28DeliveryPackageInformation. . . . . . . . . . . 28Reliability. . . . . . . . . . . . . . . . . . . . . . . . . . . 28CompatibilitywithRoHSrequirements. . . . 28SalesOfficesandContactInformation. . . . 29

1/ 28701- BMR 619 Rev. A © Flex, November 2017

PMB4518TWPDatasheet

8,80[0.346]

7,40[0.291]

51,80 [2.039]

48,26 [1.900]

Recommended footprint (customer board), no components within border.Holes: Ø1,0 [0.04] through plated holes with Ø1,5 [0.06] pads on both sides.

Note 1: For other pin lengths, refer to Product program/Ordering information

1 2 3 4 5 6 7 8 9 10

Dimensions in mm [inch]

Tolerances (unless specified):x,x +/-0,5 [0.02]x,xx +/-0,25 [0.01]

E

7,0 [0.27]

8,5 [0.33] max

choke

35,56 [1.400]

48,26 [1.900]

2,54 [0.100] (7x) (1,27 [0.05])

13,20[0.520]50,8 [2.00]

pinlength3,60[0.142]

(Note1)

1

1

Mechanical Data

Product Program

Delivery option M.o.q. Suffix Example

Tray 100pcs /B PMB4xxxTWP/B

Ordering Information

*Inputvoltagelimitedto3.8-5.5Vfor3.3Voutandforoutputvoltagesof3.3Vand4.5-5.5foroutputvoltagesabove3.3V.

VIVO/IOmax

POmax OrderingNo. CommentOutput1

3.0-5.5V* 0.8-3.6V/16A 52.8W PMB4518TWP Standardversion

Option Suffix Example

PositiveRemoteControllogic P PMB4518TWPP


PMB4518TWPDatasheet

Characteristics min typ max Unit

Tref OperatingReferenceTemperature,seepg.27 -45 +115 ˚C

TS Storagetemperature -55 +125 ˚C

VI Inputvoltage -0.3 +5.5 Vdc

Characteristics Conditions min typ max Unit

VI Inputvoltagerange 3.0 5.5 Vdc

VIoff Turn-offinputvoltageRampfromhighervoltage,Vout=1.0-2.5V,Vin=3.3V 2.2

VdcRampfromhighervoltage,Vout=3.3V,Vin=5.0V 3.4

VIon Turn-oninputvoltageRampfromlowervoltage,Vout=1.0-2.5V,Vin=3.3V 2.7

VdcRampfromlowervoltage,Vout=3.3V,Vin=5.0V 3.5

CI Inputcapacitance 20 µF

PIi Inputidlingpower Io=0A,VI=5V 680 mW

PRC Inputstand-bypower(RCactive) Nonoperation,VI=5V 7.5 mW

VIac Inputripple1) 20Hz...5MHz,Iomax,VI=5V 400 mV

Input

StressinexcessofAbsoluteMaximumRatingsmaycausepermanentdamage.

AbsoluteMaximumRatings,sometimesreferredtoasnodestructionlimits,are

normallytestedwithoneparameteratatimeexceedingthelimitsofOutputdata

orElectricalCharacteristics.Ifexposedtostressabovetheselimits,functionand

performancemaydegradeinanunspecifiedmanner.

Absolute Maximum Ratings

Tref = -30 ... +90 ˚C, VI=3.0...5.5VunlessotherwisespecifiedTypvaluesspecifiedat:Tref = +25 ˚C, VInom,Iomax=16A

1)Measuredwith2x22µFceramiccapacitors

Connections Weight7.7g

Pin Designation Function

1 +Out Positiveoutput


3 +Sense Positivesense


5 GND Ground

6 GND Ground

7 +In Positiveinput

8 +In Positiveinput

9 Vadj Outputvoltageadjust

10 RC Remotecontrol

PinsMaterial:CopperalloyPlating:Mattetinovernickel


PMB4518TWPDatasheet

Characteristics

RandomVibration IEC60068-2-64FrequencyAccelerationdensity

5...500Hz0.5g2/Hz

Mechanicalshock(halfsinus)

IEC60068-2-27PeakaccelerationDuration

50g11ms

Leadintegrity IEC60068-2-21Ub Simultaneousbending Allleads

Temperaturecycling JESD22-A104-BGTemperatureNumberofcycles

-40 ... +125 ˚C300

Accelerateddampheat JESD22-A101-B

TemperatureHumidityDurationBias

+85 ˚C85%RH1000hoursmaxinputvoltage

SolderabilityIEC60068-2-54(AgedaccordingtoJESD22-A101-B,240hnobias)

SolderimmersiondepthTimeforonsetofwettingWettingforce

2mm<2.5s>200mN/m

Cold(inoperation) IEC60068-2-1TemperatureDuration

-45 ˚C72h

Hightemperaturestorage JESD22-A103-BATemperatureDuration

+125 ˚C1000h

Product Qualification Specification

Fundamental Circuit Diagram

GNDGND

PWM

+IN +OUT

+SENSE

Vadj

controller

Ref

GND

Erroramplifier

RC RC

GND

Block


• Electrical shock• Energy hazards• Fire• Mechanical and heat hazards• Radiation hazards• Chemical hazards

On-boardDC-DCconvertersaredefinedascomponentpowersupplies.AscomponentstheycannotfullycomplywiththeprovisionsofanySafetyrequirementswithout“ConditionsofAcceptability”.ItistheresponsibilityoftheinstallertoensurethatthefinalproducthousingthesecomponentscomplieswiththerequirementsofallapplicableSafetystandardsandDirectivesforthefinalproduct.

ComponentpowersuppliesforgeneraluseshouldcomplywiththerequirementsinIEC60950,EN60950andUL60950“Safetyofinformationtechnologyequipment”.

Thereareothermoreproductrelatedstandards,e.g.IEC61204-7“Safetystandardforpowersupplies",IEEE802.3af“EthernetLAN/MANDataterminalequipmentpower”,andETS300132-2“Powersupplyinterfaceattheinputtotelecommunicationsequipment;part2:DC”,butallofthesestandardsarebasedonIEC/EN/UL60950withregardstosafety.

FlexDC/DCconvertersandDC/DCregulatorsareUL60950recognizedandcertifiedinaccordancewithEN60950.

TheflammabilityratingforallconstructionpartsoftheproductsmeetsUL94V-0.

Theproductsshouldbeinstalledintheend-useequipment,inaccordancewiththerequirementsoftheultimateapplication.NormallytheoutputoftheDC/DCconverterisconsideredasSELV(SafetyExtraLowVoltage)andtheinputsourcemustbeisolatedbyminimumDoubleorReinforcedInsulationfromtheprimarycircuit(ACmains)inaccordancewithIEC/EN/UL60950.

PMB4518TWPDatasheet

IsolatedDC/DCconverters.

ItisrecommendedthataslowblowfusewitharatingtwicethemaximuminputcurrentperselectedproductbeusedattheinputofeachDC/DCregulator.

ItisrecommendedthatafastblowfusewitharatingtwicethemaximuminputcurrentperselectedproductbeusedattheinputofeachDC/DCconverter.Ifaninputfilterisusedinthecircuitthefuseshouldbeplacedinfrontoftheinputfilter.IntherareeventofacomponentproblemintheinputfilterorintheDC/DCconverterthatimposesashortcircuitontheinputsource,thisfusewillprovidethefollowingfunctions:

• IsolatethefaultyDC/DCconverterfromtheinputpowersourcesoasnottoaffecttheoperationofotherpartsofthesystem.

• Protectthedistributionwiringfromexcessivecurrentandpowerlossthuspreventinghazardousoverheating.

Thegalvanicisolationisverifiedinanelectricstrengthtest.Thetestvoltage(VISO)betweeninputandoutputis1500Vdcor2250Vdcfor60seconds(refertoproductspecification).Leakagecurrentislessthan1µAatnominalinputvoltage.

24Vdcsystems.TheinputvoltagetotheDC/DCconverterisSELV(SafetyExtraLowVoltage)andtheoutputremainsSELVundernormalandabnormaloperatingconditions.

48and60Vdcsystems.IftheinputvoltagetoFlexDC/DCconverteris75Vdcorless,thentheoutputremainsSELV(SafetyExtraLowVoltage)undernormalandabnormaloperatingconditions.

SinglefaulttestingintheinputpowersupplycircuitshouldbeperformedwiththeDC/DCconverterconnectedtodemonstratethattheinputvoltagedoesnotexceed75Vdc.

IftheinputpowersourcecircuitisaDCpowersystem,thesourcemaybetreatedasaTNV2circuitandtestinghasdemonstratedcompliancewithSELVlimitsandisolationrequirementsequivalenttoBasicInsulationinaccordancewithIEC/EN/UL60950.

Non-isolatedDC/DCregulators.TheinputvoltagetotheDC/DCregulatorisSELV(SafetyExtraLowVoltage)andtheoutputremainsSELVundernormalandabnormaloperatingconditions.

Safety Specification

Generalinformation.FlexDC/DCconvertersandDC/DCregulatorsaredesignedinaccordancewithsafetystandardsIEC/EN/UL60950, Safety of Information Technology Equipment.

IEC/EN/UL60950containsrequirementstopreventinjuryordamageduetothefollowinghazards:


PMB4518TWPDatasheet

Characteristics ConditionsOutput

Unitmin typ max

VOi Outputvoltageadjustedsetting Tref=+25°C,VInom,IOmax,Radj80kΩ 0.98 1.00 1.02 V

VO

Outputvoltagetoleranceband IO=0.01...1.0xIOmax 0.97 1.03 V

Idlingvoltage IO=0 0.98 1.02 V

Lineregulation VImin...VImax,IOmax 11 mV

Loadregulation IO=0.01...1.0xIOmax,VInom 10 mV

VtrLoadtransientvoltagedeviation

Loadstep=0.25...0.75xIOmax,dI/dt=5A/µs,CO=150µF,VI=3.3V

100 mV

ttr Loadtransientrecoverytime 60 µs

Tcoeff Temperaturecoefficient Tref=-30...+90°C,IOmax -0.1 0 +0.1 mV/°C

ts Start-uptimeFromVIconnectedtoVO=0.9xVOI,IO=0.1...1.0xIOmax,VInom

8.5 ms

tr Ramp-uptime 0.1...0.9xVO,IO=0.1...1.0xIOmax,VInom 4 ms

tr Falltime,VOx0.1 IO=IOmax,VInom 0.2 ms

tr Falltime,VOx0.1 IO=0A,VInom 5 s

tRCoff RCshut-downtimetoVOx0.1 IO=IOmax,VInom 0.2 ms

tRCon RCstart-uptimetoVOx0.9 IO=IOmax,VInom 8 ms

tRC RCfalltime,VOx0.1...0.9 IO=0A,VInom 10 s

IO Outputcurrent 0 16 A

POmax Maxoutputpower AtVO=VOnom 16 W

Ilim Currentlimitthreshold Tref<Trefmax 22 28 35 A

VOac Outputripple 20Hz...5MHz,IOmax 10 20 mVp-p

η Efficiency-50%load IO=0.5xIOmax,VI=5V 87.2 %

η Efficiency-100%load IO=IOmax,VI=5V 81 83.4 %

Pd PowerDissipation IO=IOmax,VI=5V 3.1 3.8 W

Fo Switchingfrequency IO=0...1.0xIOmax 250 300 350 kHz

Isense Remotesensecurrent 8 mA

II Staticinputcurrent VI=3.0V,IO=IOmax,Tref=25°C 6.7 A

MTBF Predictedreliability Tref=40°C 6millionhours

Tref=-30...+90°C,VI=3.0...5.5Vunlessotherwisespecified.Inputfilter2x22µF,Outputfilter1x150µFTypvaluesspecifiedat:Tref=+25°CandVInom.IOmax=16A.Note:+Senseconnectedto+Out

Adjusted to 1.0 V out - Data


PMB4518TWPDatasheet

Output Current Derating at V input

Start-Up

Outputvoltagevs.loadcurrent.

Availableloadcurrentvs.ambientairtemperatureandairflowatVin=5V.Seeconditionsonpage27.

Start-upatIO=16AresistiveloadatTref=+25°C,Vin=3.3V.StartenabledbyconnectingVin.Toptrace:outputvoltage(0.5V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.

Efficiency Power Dissipation

Output Characteristics

Adjusted to 1.0 V out - Typical Characteristics

Efficiencyvs.loadcurrentandinputvoltageatTref=+25°C Dissipatedpowervs.loadcurrentandinputvoltageatTref=+25°C

Generalconditions:Inputfilter2x22µF,Outputfilter1x150µF

Output Current Derating at . V input

Availableloadcurrentvs.ambientairtemperatureandairflowatVin=3.3V.Seeconditionsonpage27.


PMB4518TWPDatasheet

Turn Off Output Ripple

Transient with 10 µFoutputcapacitor

Outputvoltageresponsetoloadcurrentstep-change(4-12-4A)atTref=+25°C,Vin=3.3V.dI/dt=5A/µsToptrace:outputvoltage(ac)(100mV/div.).Bottomtrace:loadcurrent(dc)(10A/div.)Timescale:0.1ms/div.



Outputvoltageripple(20mV/div.)atTref=+25°C,Vin=3.3V,IO=16Aresistiveload.Bandwidth=5MHz.Timescale:2µs/div.

Turn-offatIO=16AresistiveloadatTref=+25°C,Vin=3.3V.Turn-offenabledbydisconnectingVin.Toptrace:outputvoltage(0.5V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.

Adjusted to 1.0 V out - Typical CharacteristicsGeneralconditions:Inputfilter2x22µF,Outputfilter1x150µF


PMB4518TWPDatasheet

Tref=-30...+90°C,VI=3.0...5.5Vunlessotherwisespecified.Inputfilter2x22µF,Outputfilter1x150µFTypvaluesspecifiedat:Tref=+25°CandVInom,IOmax=16A.Note:+Senseconnectedto+Out

Adjusted to 1. V out - Data


Unitmin typ max


VO







120 mV




8.5 ms








POmax Maxoutputpower AtVO=VOnom 19.2 W



η Efficiency-50%load IO=0.5xIOmax,VI=5V 89 %

η Efficiency-100%load IO=IOmax,VI=5V 82.7 85.1 %







10PMB4518TWPDatasheet


Output Characteristic Start-Up





Adjusted to 1. V - Typical Characteristics

Efficiencyvs.loadcurrentandinputvoltageatTre=+25°C Dissipatedpowervs.loadcurrentandinputvoltageatTref=+25°C













Adjusted to 1. V - Typical CharacteristicsGeneralconditions:Inputfilter2x22µF,Outputfilter1x150µF




Unitmin typ max


VO







120 mV




8.5 ms




























Adjusted to 1.V out - Typical Characteristics














Adjusted to 1.V out - Typical CharacteristicsGeneralconditions:Inputfilter2x22µF,Outputfilter1x150µF



Tref=–30…+90°C,VI=3.0...5.5Vunlessotherwisespecified.Inputfilter2x22µF,Outputfilter1x150µFTypvaluesspecifiedat:Tref=+25°CandVInom.IOmax=16A.Note:+Senseconnectedto+Out



Unitmin typ max


VO







110 mV




8.5 ms




















Efficiency

Output Current Derating at . V input Output Current Derating at V input

Adjusted to 1. V - Typical Characteristics




Efficiencyvs.loadcurrentandinputvoltageatTref=+25°C



Power Dissipation

Dissipatedpowervs.loadcurrentandinputvoltageatTref=+25°C





Adjusted to 1. V out - Typical Characteristics











Unitmin typ max


VO







160 mV




8.5 ms












η Efficiency-100%load IO=IOmax,VI=5V 90 92 %







Adjusted to . V out - Data







Start-upatIO=16AresistiveloadatTref=+25°C,Vin=3.3V.StartenabledbyconnectingVin.Toptrace:outputvoltage(1V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.


Adjusted to . V out - Typical Characteristics













Turn-offatIO=16AresistiveloadatTref=+25°C,Vin=3.3V.Turn-offenabledbydisconnectingVin.Toptrace:outputvoltage(1V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.

Adjusted to . V out - Typical CharacteristicsGeneralconditions:Inputfilter2x22µF,Outputfilter1x150µF



Tref=-30...+90°C,VI=3.8...5.5Vunlessotherwisespecified.Inputfilter2x22µF,Outputfilter1x150µFTypvaluesspecifiedat:Tref=+25°CandVI=5.0V.IOmax=16A.Note:+Senseconnectedto+Out

Adjusted to . V out - Data


Unitmin typ max

VOi Outputvoltageadjustedsetting Tref=+25°C,VI>3.8V,IOmax,Radj3.1kΩ 3.234 3.3 3.366 V

VO



Lineregulation VI=5V...VImax,IOmax 11 mV

Loadregulation IO=0.01...1.0xIOmax,VI=5V 20 mV


Loadstep=0.25...0.75xIOmax,dI/dt=5A/µs,CO=150µF,VI=5V

120 mV



ts Start-uptimeFromVIconnectedtoVO=0.9xVOadj,IO=0.1...1.0xIOmax,VI=5V

8.5 ms

tr Ramp-uptime0.1...0.9xVO,IO=0.1...1.0xIOmax,VI=5V

4 ms

tr Falltime,VOx0.1 IO=IOmax,VI=5V 0.2 ms

tr Falltime,VOx0.1 IO=0A,VI=5V 5 s

tRCoff RCshut-downtimetoVOx0.1 IO=IOmax,VI=5V 0.2 ms

tRCon RCstart-uptimetoVOx0.9 IO=IOmax,VI=5V 8 ms

tRC RCfalltime,VOx0.1...0.9 IO=0A,VI=5V 5 s





η Efficiency-50%load IO=0.5xIOmax,VI=5V 95.4 %

η Efficiency-100%load IO=IOmax,VI=5V 92 94 %







PMB4518TWPDatasheet

Output Current Derating at V inputOutput Characteristic

Start-Up

Outputvoltagevs.loadcurrent. Availableloadcurrentvs.ambientairtemperatureandairflowatVin=5V.Seeconditionsonpage27.

Start-upatIO=16AresistiveloadatTref=+25°C,Vin=5V.StartenabledbyconnectingVin.Toptrace:outputvoltage(1V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.


Adjusted to . V out - Typical Characteristics



Turn Off

Turn-offatIO=16AresistiveloadatTref=+25°C,Vin=5V.Turn-offenabledbydisconnectingVin.Toptrace:outputvoltage(1V/div.).Bottomtrace:inputvoltage(2V/div.).Timescale:2ms/div.


PMB4518TWPDatasheet

Output Ripple Transient with 10 µFoutputcapacitor

Outputvoltageresponsetoloadcurrentstep-change(4-12-4A)atTref=+25°C,Vin=5V.dI/dt=5A/µsToptrace:outputvoltage(ac)(100mV/div.).Bottomtrace:loadcurrent(dc)(10A/div.)Timescale:0.1ms/div.


Outputvoltageresponsetoloadcurrentstep-change(4-12-4A)atTref=+25°C,Vin=5V.dI/dt=5A/µsToptrace:outputvoltage(ac)(100mV/div.).Bottomtrace:loadcurrent(dc)(10A/div.)Timescale:0.1ms/div.

Outputvoltageripple(20mV/div.)atTref=+25°C,Vin=5V,IO=16Aresistiveload.Bandwidth=5MHz.Timescale:2µs/div.

Adjusted to . V out - Typical CharacteristicsGeneralconditions:Inputfilter2x22µF,Outputfilter1x150µF


PMB4518TWPDatasheet

RCRegulatorcondition

min typ max Unit

HighlevelreferencedtoGND

OFF 1.7 5.5 V

Open ON

EMC Specification

Layout Recommendation TheradiatedEMIperformanceoftheDC/DCregulatorwillbeoptimisedbyincludingagroundplaneinthePCBareaundertheDC/DCregulator.Thisapproachwillreturnswitchingnoisetogroundasdirectlyaspossible,withimprovementstobothemissionandsusceptibility.

Operating Information

Remote Control (RC)TheRCpinmaybeusedtoturnonorturnofftheregulatorusingasuitableopencollectorfunction.TurnoffisachievedbyconnectingtheRCpintotheinputvoltage.

TheregulatorwillruninnormaloperationwhentheRCpinisleftopen.

AllPMB4000SeriesDC/DCregulatorshaveapositivere-motesensepinthatcanbeusedtocompensateformoder-ateamountsofresistanceinthedistributionsystemandal-lowforvoltageregulationattheloadorotherselectedpoint.Theremotesenselinewillcarryverylittlecurrentanddoesnotneedalargecrosssectionalarea.However,thesenselineonthePCBshouldbelocatedclosetoagroundtraceorgroundplane.Theremotesensecircuitrywillcompensateforupto10%voltagedropbetweenthesensevoltageandthevoltageattheoutputpinsfromVOnom.Iftheremotesenseisnotneededthesensepinshouldbeleftopen.

Remote Sense

RC

Vi

Module

Vi

GND


PMB4518TWPDatasheet

Input And Output Impedance


Output Voltage Adjust (Vadj)

Theoutputvoltagecanbesetbymeansofanexternalresistor,connectedtotheVadjpin.Nominaloutputvoltage0.75VissetbyleavingtheVadjpinopen.Adjustmentcanonlybemadetoincreasetheoutputvoltagesetting.

Toincrease:Connectaresistorbetween(Vadj)and(Gnd).Theoutputvoltageincreaseswithdecreasingresistorvalueasshowninthetablebelow.Notethatthemaximumoutputvoltage3.63Vmaynotbeexceeded.

Rextup(kohm)=(21.007/(VO-0.75225))-5.1

Circuitconfigurationforoutputvoltageadjust

Increase

+Out

GND

VadjLoad

Radj

Sense

OutputVoltage(V) Resistor(ohm)

0.75 Open

1.0 79.691k

1.2 41.817k

1.5 22.990k

1.8 14.949k

2.5 6.919k

3.3 3.145k

Current Limit Protection ThePMB4000SeriesDC/DCregulatorsincludecurrentlimitingcircuitrythatallowsthemtowithstandcontinuousoverloadsorshortcircuitconditionsontheoutput.Thecur-rentlimitisofhick-upmodetype.Theregulatorwillresumenormaloperationafterremovaloftheoverload.Theloaddistributionsystemshouldbedesignedtocarrythemaximumoutputshortcircuitcurrentspecified.

Input And Output ImpedanceTheimpedanceofboththepowersourceandtheloadwillinteractwiththeimpedanceoftheDC/DCregulator.Itismostimportanttohavealowcharacteristicimpedance,bothattheinputandoutput,astheregulatorshavealowenergystoragecapability.Usecapacitorsacrosstheinputifthesourceinductanceisgreaterthan4.7µH.Suitableinputcapacitorsare22µF-220µFlowESRceramics.

Maximum Capacitive LoadWhenpoweringloadswithsignificantdynamiccurrentrequirements,thevoltageregulationattheloadcanbeimprovedbyadditionofdecouplingcapacitanceattheload.ThemosteffectivetechniqueistolocatelowESRceramiccapacitorsasclosetotheloadaspossible,usingseveralcapacitorstolowerthetotalESR.Theseceramiccapacitorswillhandleshortdurationhigh-frequencycomponentsofdynamicloadchanges.Inaddition,highervaluesofcapacitors(electrolyticcapacitors)shouldbeusedtohandlethemid-frequencycomponents.ItisequallyimportanttousegooddesignpracticewhenconfiguringtheDCdistributionsystem.

LowresistanceandlowinductancePCBlayoutsandcablingshouldbeused.Rememberthatwhenusingremotesensing,allresistance(includingtheESR),inductanceandcapacitanceofthedistributionsystemiswithinthefeedbackloopoftheregulator.Thiscanaffectontheregulatorscompensationandtheresultingstabilityanddynamicresponseperformance.

VerylowESRandhighcapacitancemustbeusedwithcare.A“ruleofthumb”isthatthetotalcapacitancemustneverexceedtypically500-700µFifonlylowESR(<2mΩ)ceramiccapacitorsareused.Ifmorecapacitanceisneeded,acombinationoflowESRtypeandelectrolyticcapacitorsshouldbeused,otherwisethestabilitywillbeaffected.

ThePMB4000seriesregulatorcanacceptupto8mFofcapacitiveloadontheoutputatfullload.Thisgives<500µF/AofIO.Whenusingthatlargecapacitanceitisimportanttoconsidertheselectionofoutputcapacitors;theresultingbehaviorisacombinationoftheamountofcapacitanceandESR.

Minimum Required External Capacitors

Externalinputcapacitorsarerequiredtoincreasethelifetimeoftheinternalcapacitorsandtofurtherreducetheinputripple.Aminimumof2x22µF external input capaci-µF external input capaci-Fexternalinputcapaci-tancewithlowESRshouldbeadded.

Aminimumof150µF external output capacitance, low ESR,µF external output capacitance, low ESR,Fexternaloutputcapacitance,lowESR,shouldbeaddedfortheconvertertooperateproperlyatfullload.


PMB4518TWPDatasheet


Parallel OperationThePMB4000SeriesDC/DCregulatorscanbeconnectedinparallelwithacommoninput.Parallelingisaccomplishedbyconnectingtheoutputvoltagepinsdirectlyandusingaloadsharingdeviceontheinput.Layoutconsiderationsshouldbemadetoavoidloadimbalance.Formoredetailsonparallel-

ing,pleaseconsultyourlocalapplicationssupport.

Input Undervoltage LockoutThePMB4000SeriesDC/DCregulatorsareequippedwithalockoutfunctionforlowinputvoltage.Whentheinputvoltageisbelowtheundervoltagelockoutlimitoftheregulatoritwillshutoff.Whentheinputvoltageincreasesabovethelockout

leveltheregulatorwillturnon.

AcombinationoflowESRandoutputcapacitanceexceeding8mFcancausetheregulatorintoovercurrentprotectionmode(hick-up)duetohighstartupcurrent.TheoutputfiltermustthereforebedesignedwithoutexceedingtheabovestatedcapacitancelevelsiftheESRislowerthan30-40mΩ.


PMB4518TWPDatasheet

Thermal Considerations

GeneralThePMB4000SeriesDC/DCregulatorsaredesignedtooperateinavarietyofthermalenvironments,howeversufficientcoolingshouldbeprovidedtohelpensurereliableoperation.Heatisremovedbyconduction,convectionandradiationtothesurroundingenvironment.Increasedairflowenhancestheheattransferviaconvection.Propercoolingcanbeverifiedbymeasuringthetemperatureatthereferencepoint(Tref).

Calculation of ambient temperature

Byusingthethermalresistancethemaximumallowedambienttemperaturecanbecalculated.

A.Thepowerlossiscalculatedbyusingtheformula((1/η )-1)×outputpower=powerlosses.η=efficiencyofregulator.Example:95%=0.95

B.FindthevalueofthethermalresistanceRthTref-Ainthedia-grambyusingtheairflowspeedatthemodule.Takethether-malresistance×powerlosstogetthetemperatureincrease.

Thermalresistancevs.airspeedmeasuredattheregulator.

C.Maxallowedcalculatedambienttemperatureis:MaxTrefofDC/DCregulator-temperatureincrease.

Example:5Vinput,1.8Voutputat1m/s,fullload:

B. 3.2W×9°C/W=28.8°C

C. 90°C-28.8°C=maxambienttemperatureis61.2°C

Therealtemperaturewillbedependentonseveralfactors,likePCBsizeandtype,directionofairflow,airturbulenceetc.Itisrecommendedtoverifythetemperaturebytesting.

A. ((1/0.9)-1)×28.8W=3.2W

ThePMB4000thermaltestingisperformedwiththeproductmountedonanFR4board254× 254 mm with 8× 254 mm with 8254mmwith8layersof35µm copper. Airflow is perpendicular to the Tµm copper. Airflow is perpendicular to the Tmcopper.AirflowisperpendiculartotheTrefside.

25m

m[1

in.]

airflow

Test board

choke


PMB4518TWPDatasheet

Soldering InformationThePMB4000seriesDC/DCregulatorsareintendedformanualorwavesoldering.Theplasticbodyofthepinconnectorsresistssolderingheatforlimitedtimeupto260°C..

Whenhandsoldering,careshouldbetakentoavoiddirectcontactbetweenthehotsolderingirontipandthepinsformorethanafewsecondsinordertoavoidmeltingoftheplastic.

Delivery Package InformationThePMB4000seriesregulatorsaredeliveredinantistatictrayswithJedecstandardouterdimensions.Traycapacity25pcs.Eachboxcontains4trays.

ReliabilityTheMeanTimeBetweenFailure(MTBF)ofthePMB4000seriesDC/DCregulatorfamilyiscalculatedtobegreaterthan6millionhoursatfulloutputpowerandareferencetemperatureof+40°CusingTelCordiaSR332.

Compatibility with RoHS requirementsThe products are compatible with the relevant clauses and requirements of the RoHS directive 2011/65/EU and have a maximum concentration value of 0.1% by weight in homogeneous materials for lead, mercury, hexavalent chromium, PBB and PBDE and of 0.01% by weight in homogeneous materials for cadmium.

Exemptions in the RoHS directive utilized in Flex products are found in the Statement of Compliance document.

Flex fulfills and will continuously fulfill all its obligations under regulation (EC) No 1907/2006 concerning the registration, evaluation, authorization and restriction of chemicals (REACH) as they enter into force and is through product materials declarations preparing for the obligations to communicate information on substances in the products.

© Flex 2017

The information and specifications in this technical specification is believed to be correct at the time of publication. However, no liability is accepted for inaccuracies, printing errors or for any consequences thereof. Flex reserves the right to change thecontents of this technical specification at any time without prior notice.


DC/DC regulator Input 3.0 - 5.5 V Output 16 A

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