- 4 -`

AUGUST08,2012|DATASHEET| Rev3.1

IR3894

12AHighlyIntegratedSupIRBuck

Single‐InputVoltage,SynchronousBuckRegulator

PD‐97745

PINDESCRIPTIONS

PIN # PIN NAME PIN DESCRIPTION

1 Fb

Invertinginputtotheerroramplifier.Thispinisconnecteddirectlytotheoutput

oftheregulatorviaresistordividertosettheoutputvoltageandprovide

feedbacktotheerroramplifier.

2 Vref

Internalreferencevoltage,itcanbeusedformarginingoperationalso. In

normalandsequencingmodeoperation,Vrefisleftfloating.A1nFceramic

capacitorisrecommendedbetweenthispinandGnd.Intrackingmode

operation,VrefshouldbetiedtoGnd.

3 Comp

Outputoferroramplifier.Anexternalresistorandcapacitornetworkistypically

connectedfromthispintoFbtoprovideloopcompensation.

4 Gnd Signalgroundforinternalreferenceandcontrolcircuitry.

5 Rt/Sync

Multi‐functionpintosetswitchingfrequency.Useanexternalresistorfromthis

pintoGndtosetthefree‐runningswitchingfrequency.Anexternalclocksignal

toconnecttothispinthroughadiode,thedevice’sswitchingfrequencyis

synchronizedwiththeexternalclock.

6 S_Ctrl

Softstart/stopcontrol.Ahighlogicinputenablesthedevicetogointothe

internalsoftstart;alowlogicinputenablestheoutputsoftdischarged.Pullthis

pintoVccifthisfunctionisnotused.

7 PGood

PowerGoodstatuspin.Outputisopendrain.Connectapullupresistorfrom

thispintothevoltagelowerthanorequaltotheVcc.

8 Vsns

Sensepinforover‐voltageprotectionandPGood.Itisoptionaltotiethispinto

FbpindirectlyinsteadofusingaresistordividerfromVout.

9 Vin

InputvoltageforInternalLDO.A1.0µFcapacitorshouldbeconnectedbetween

thispinandPGnd.IfexternalsupplyisconnectedtoVcc/LDO_outpin,thispin

shouldbeshortedtoVcc/LDO_Outpin.

10 Vcc/LDO_Out

InputBiasVoltage,outputofinternalLDO.Placeaminimum2.2µFcapfromthis

pintoPGnd.

11 PGnd

PowerGround.ThispinservesasaseparatedgroundfortheMOSFETdrivers

andshouldbeconnectedtothesystem’spowergroundplane.

12 SW Switchnode.Thispinisconne ctedtotheoutputinductor.

13 PVin Inputvoltageforpowerstage.

14 Boot

Supplyvoltageforhighsidedriver,a100nFcapacitorshouldbeconnected

betweenthispinandSWpin.

15 Enable

Enablepintoturnonandoffthedevice,ifthispinisconnectedtoPVinpin

througharesistordivider,inputvoltageUVLOcanbeimplemented.

16 Vp

Inputtoerroramplifierfortrackingpurposes.Inthenormaloperation,itisleft

floatingandnoexternalcapacitorisrequired.Inthesequencingorthetracking

modeoperation,anexternalsignalcanbeappliedasthereference.

17 Gnd Signalgroundforinternalreferenceandcontrolcircuitry.





- 5 -`

AUGUST08,2012|DATASHEET| Rev3.1

IR3894

12AHighlyIntegratedSupIRBuck

Single‐InputVoltage,SynchronousBuckRegulator

PD‐97745

ABSOLUTEMAXIMUMRATINGS



Stressesbeyondthoselistedunder“AbsoluteMaximumRatings”maycausepermanentdamagetothedevice.Theseare

stressratingsonlyandfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedinthe

operationalsectionsofthespecificationsarenotimplied.



PVin,Vin ‐0.3Vto25V

Vcc/LDO_Out‐0.3Vto8V(Note2)

Boot ‐0.3Vto33V

SW‐0.3Vto25V(DC),‐4Vto25V(AC,100ns)

BoottoSW ‐0.3VtoVcc+0.3V(Note1)

S_Ctrl,PGood‐0.3VtoVcc+0.3V(Note1)

OtherInput/OutputPins ‐0.3Vto+3.9V

PGndtoGnd‐0.3Vto+0.3V

StorageTemperatureRange ‐55°Cto150°C

JunctionTemperatureRange‐40°Cto150°C(Note2)

ESDClassification(HBMJESD22‐A114) 2kV

MoistureSensitivityLevel JEDECLevel3@260°C



Note1:Mustnotexceed8V



Note2:Vccmustnotexceed7.5VforJunctionTemperaturebetween‐10°Cand‐40°C



- 6 -`

AUGUST08,2012|DATASHEET| Rev3.1

IR3894

12AHighlyIntegratedSupIRBuck

Single‐InputVoltage,SynchronousBuckRegulator

PD‐97745

ELECTRICALSPECIFICATIONS

RECOMMENDEDOPERATINGCONDITIONSFORRELIABLEOPERATIONWITHMARGIN

 SYMBOL MIN MAX

UNITS

InputVoltageRange* PV

 1.0 21

V



InputVoltageRange** V

 6.8 21

SupplyVoltageRange*** V

 4.5 7.5

SupplyVoltageRange BoottoSW 4.5 7.5

OutputVoltageRange V

 0.5 0.86xVin

OutputCurrentRange I

 0 ±12 A

SwitchingFrequency F

 300 1500 kHz

OperatingJunctionTemperature T

‐40 125 °C

*MaximumSWnodevoltageshouldnotexceed25V.

**Forinternallybiasedsinglerailoperation.

***Vcc/LDO_outcanbeconnectedtoanexternalregulatedsupply.Ifso,theVininputshouldbeconnectedtoVcc/LDO_outpin.

ELECTRICALCHARACTERISTICS

Unlessotherwisespecified,thesespecificationsapplyover,6.8V<Vin=PVin<21V,Vref=0.5Vin0°C<T

<125°C.

TypicalvaluesarespecifiedatT

=25°C.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNIT

PowerStage

PowerLosses P

LOSS



Vin



=12V,V

=1.2V,I

=12A,

Fs=600kHz,L=0.51uH,

Vcc=6.4V(InternalLDO),Note4

 2.1 W

TopSwitch R

ds(on)_Top

 VBoot‐Vsw=6.4V,I

=12A,T

=25°C 13.2 17.2

mΩ

BottomSwitch R

ds(on)_Bot

 Vcc=6.4V,I

=12A7.2 9.4

BootstrapDiodeForwardVoltage I(Boot)=15mA 200 300 500 mV

SWLeakageCurrent



SW=0V,Enable=0V

1 µA

SW=0V,Enable=high,

Vp=0V



DeadBandTime T

 Note420 ns

SupplyCurrent

VINSupplyCurrent(standby) I

in(Standby)

 EN=Low,NoSwitching100 µA

VINSupplyCurrent(dynamic)

in(Dyn)



EN=High,Fs=600kHz,

Vin=PVin=21V



14 18

mA

VCCLDOOutput

OutputVoltage



Vin(min)=6.8V,Icc=0‐50mA,

Cload=2.2uF,DCM=0

6.0 6.4 6.7

V

Vin(min)=6.8V,Icc=0‐50mA,

Cload=2.2uF,DCM=1

4.0 4.4 4.85

VCCDropout V

cc_drop

Icc=50mA,Cload=2.2uF0.8 V

ShortCircuitCurrent Ishort  70mA

Zero‐crossingComparatorDelay Tdly_zc Note4256/Fs s

Part #	ERJ-3EKF1000V
Description	RES THKFLM 0603 100 OHM 1% 1/10W 100PPM/ C SMD - Cut TR (S
Category	CHIP RESISTOR
Availability	Out of Stock
Qty	0

ERJ-3EKF1000V

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