LF411
LowOffset,LowDriftJFETInputOperationalAmplifier
GeneralDescription
Thesedevicesarelowcost,highspeed,JFETinputopera-tionalamplifierswithverylowinputoffsetvoltageandguar-anteedinputoffsetvoltagedrift.Theyrequirelowsupplycur-rentyetmaintainalargegainbandwidthproductandfastslewrate.Inaddition,wellmatchedhighvoltageJFETinputdevicesprovideverylowinputbiasandoffsetcurrents.TheLF411ispincompatiblewiththestandardLM741allowingdesignerstoimmediatelyupgradetheoverallperformanceofexistingdesigns.
Theseamplifiersmaybeusedinapplicationssuchashighspeedintegrators,fastD/Aconverters,sampleandholdcir-cuitsandmanyothercircuitsrequiringlowinputoffsetvolt-ageanddrift,lowinputbiascurrent,highinputimpedance,highslewrateandwidebandwidth.
Features
Internallytrimmedoffsetvoltage:0.5mV(max)Inputoffsetvoltagedrift:10µV/˚C(max)Lowinputbiascurrent:50pALowinputnoisecurrent:
Widegainbandwidth:3MHz(min)Highslewrate:10V/µs(min)Lowsupplycurrent:1.8mAHighinputimpedance:1012Ω
LowtotalharmonicdistortionAV=10,
RL=10k,VO=20Vp-p,BW=20Hz−20kHz:<0.02%nLow1/fnoisecorner:50Hz
nFastsettlingtimeto0.01%:2µsnnnnnnnnn
TypicalConnectionConnectionDiagrams
MetalCanPackage
DS005655-5
Note:Pin4connectedtocase.
DS005655-1
TopView
OrderNumberLF411ACHorLF411MH/883(Note1)SeeNSPackageNumberH08A
Dual-In-LinePackage
OrderingInformation
LF411XYZ
XindicateselectricalgradeYindicatestemperaturerange
“M”formilitary“C”forcommercialZindicatespackagetype
“H”or“N”
BI-FETII™isatrademarkofNationalSemiconductorCorporation.
©1999NationalSemiconductorCorporationDS005655www.national.com
SimplifiedSchematic
DS005655-6
Note1:AvailableperJM38510/11904
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AbsoluteMaximumRatings(Note2)
IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.SupplyVoltage
DifferentialInputVoltageInputVoltageRange(Note3)
OutputShortCircuitDurationPowerDissipation(Notes4,11)
LF411A±22V±38V
LF411±18V±30V
TjmaxθjA
±19V
ContinuousHPackage670mW
±15V
ContinuousNPackage670mW(Note6)
θjC
OperatingTemp.Range
StorageTemp.RangeLeadTemp.(Soldering,10sec.)
ESDTolerance
HPackage150˚C
162˚C/W(StillAir)65˚C/W(400LF/min
AirFlow)20˚C/W
(Note5)−65˚C≤TA≤150˚C
260˚C
NPackage115˚C120˚C/W
(Note5)−65˚C≤TA≤150˚C
260˚C
Ratingtobedetermined.
DCElectricalCharacteristics
SymbolVOS∆VOS/∆TIOSParameterInputOffsetVoltageAverageTCofInputOffsetVoltageInputOffsetCurrent
VS=±15V(Notes6,8)
IBInputBiasCurrent
VS=±15V(Notes6,8)
RINAVOLInputResistanceLargeSignalVoltageGain
VOVCMCMRRPSRRISOutputVoltageSwingInputCommon-ModeVoltageRangeCommon-ModeRejectionRatioSupplyVoltageRejectionRatioSupplyCurrent
(Note9)RS≤10k
Conditions
Min
RS=10kΩ,TA=25˚CRS=10kΩ(Note7)
Tj=25˚CTj=70˚CTj=125˚CTj=25˚CTj=70˚CTj=125˚C
Tj=25˚C
VS=±15V,VO=±10V,RL=2k,TA=25˚COverTemperatureVS=±15V,RL=10k
LF411ATyp0.3725
Max0.510100225
50
200450
10
5025
12LF411
Min
Typ0.8725
Max2.020(Note7)100225
50
200450
10
2515
12UnitsmVµV/˚CpAnAnApAnAnAΩV/mVV/mVVVVdBdB
3.4
mA
200200
200200
±12±16
8080
±13.5
+19.5−16.51001001.8
2.8
±12±11
7070
±13.5
+14.5−11.51001001.8
ACElectricalCharacteristic
SymbolSRGBWeninSlewRate
Gain-BandwidthProductEquivalentInputNoiseVoltageEquivalentInputNoiseCurrent
Parameter
(Note6)Conditions
Min
LF411ATyp154250.01
Max
Min82.7
103
LF411Typ154250.01
Max
V/µsMHzUnits
VS=±15V,TA=25˚CVS=±15V,TA=25˚CTA=25˚C,RS=100Ω,f=1kHz
TA=25˚C,f=1kHz
Note2:“AbsoluteMaximumRatings”indicatelimitsbeyondwhichdamagetothedevicemayoccur.OperatingRatingsindicateconditionsforwhichthedeviceisfunctional,butdonotguaranteespecificperformancelimits.
Note3:Unlessotherwisespecifiedtheabsolutemaximumnegativeinputvoltageisequaltothenegativepowersupplyvoltage.
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ACElectricalCharacteristic
(Note6)(Continued)
Note4:Foroperatingatelevatedtemperature,thesedevicesmustbederatedbasedonathermalresistanceofθjA.
Note5:Thesedevicesareavailableinboththecommercialtemperaturerange0˚C≤TA≤70˚Candthemilitarytemperaturerange−55˚C≤TA≤125˚C.Thetemperaturerangeisdesignatedbythepositionjustbeforethepackagetypeinthedevicenumber.A“C”indicatesthecommercialtemperaturerangeandan“M”indicatesthemilitarytemperaturerange.Themilitarytemperaturerangeisavailablein“H”packageonly.
Note6:Unlessotherwisespecified,thespecificationsapplyoverthefulltemperaturerangeandforVS=±20VfortheLF411AandforVS=±15VfortheLF411.VOS,IB,andIOSaremeasuredatVCM=0.
Note7:TheLF411Ais100%testedtothisspecification.TheLF411issampletestedtoinsureatleast90%oftheunitsmeetthisspecification.
Note8:Theinputbiascurrentsarejunctionleakagecurrentswhichapproximatelydoubleforevery10˚Cincreaseinthejunctiontemperature,Tj.Duetolimitedpro-ductiontesttime,theinputbiascurrentsmeasuredarecorrelatedtojunctiontemperature.Innormaloperationthejunctiontemperaturerisesabovetheambienttem-peratureasaresultofinternalpowerdissipation,PD.Tj=TA+θjAPDwhereθjAisthethermalresistancefromjunctiontoambient.Useofaheatsinkisrecommendedifinputbiascurrentistobekepttoaminimum.
Note9:Supplyvoltagerejectionratioismeasuredforbothsupplymagnitudesincreasingordecreasingsimultaneouslyinaccordancewithcommonpractice,from±15Vto±5VfortheLF411andfrom±20Vto±5VfortheLF411A.Note10:RETS411XforLF411MHandLF411MJmilitaryspecifications.
Note11:Max.PowerDissipationisdefinedbythepackagecharacteristics.OperatingthepartneartheMax.PowerDissipationmaycausetheparttooperateout-sideguaranteedlimits.
TypicalPerformanceCharacteristics
InputBiasCurrent
InputBiasCurrent
SupplyCurrent
DS005655-11DS005655-12DS005655-13
PositiveCommon-ModeInputVoltageLimitNegativeCommon-ModeInputVoltageLimit
PositiveCurrentLimit
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DS005655-14
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TypicalPerformanceCharacteristics
NegativeCurrentLimit
(Continued)
OutputVoltageSwing
OutputVoltageSwing
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GainBandwidthBodePlotSlewRate
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DistortionvsFrequency
UndistortedOutputVoltageSwingOpenLoopFrequencyResponse
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TypicalPerformanceCharacteristics
Common-ModeRejectionRatio
PowerSupplyRejectionRatio
(Continued)
EquivalentInputNoiseVoltage
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OpenLoopVoltageGainOutputImpedanceInverterSettlingTime
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PulseResponse
RL=2kΩ,CL10pF
SmallSignalNon-Inverting
SmallSignalInverting
DS005655-39
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PulseResponse
RL=2kΩ,CL10pF(Continued)
LargeSignalNon-Inverting
LargeSignalInverting
DS005655-41DS005655-42
CurrentLimit(RL=100Ω)
DS005655-43
ApplicationHints
TheLF411seriesofinternallytrimmedJFETinputopamps(BI-FETII™)provideverylowinputoffsetvoltageandguar-anteedinputoffsetvoltagedrift.TheseJFETshavelargere-versebreakdownvoltagesfromgatetosourceanddraineliminatingtheneedforclampsacrosstheinputs.Therefore,largedifferentialinputvoltagescaneasilybeaccommodatedwithoutalargeincreaseininputcurrent.Themaximumdif-ferentialinputvoltageisindependentofthesupplyvoltages.However,neitheroftheinputvoltagesshouldbeallowedtoexceedthenegativesupplyasthiswillcauselargecurrentstoflowwhichcanresultinadestroyedunit.
Exceedingthenegativecommon-modelimitoneitherinputwillforcetheoutputtoahighstate,potentiallycausingare-versalofphasetotheoutput.Exceedingthenegativecommon-modelimitonbothinputswillforcetheamplifieroutputtoahighstate.Inneithercasedoesalatchoccursinceraisingtheinputbackwithinthecommon-moderangeagainputstheinputstageandthustheamplifierinanormaloperatingmode.
Exceedingthepositivecommon-modelimitonasingleinputwillnotchangethephaseoftheoutput;however,ifbothin-putsexceedthelimit,theoutputoftheamplifiermaybeforcedtoahighstate.
Theamplifierwilloperatewithacommon-modeinputvoltageequaltothepositivesupply;however,thegainbandwidthandslewratemaybedecreasedinthiscondition.Whenthenegativecommon-modevoltageswingstowithin3Vofthenegativesupply,anincreaseininputoffsetvoltagemayoc-cur.
TheLF411isbiasedbyazenerreferencewhichallowsnor-malcircuitoperationon±4.5Vpowersupplies.Supplyvolt-ageslessthanthesemayresultinlowergainbandwidthandslewrate.
TheLF411willdrivea2kΩloadresistanceto±10Voverthefulltemperaturerange.Iftheamplifierisforcedtodriveheavierloadcurrents,however,anincreaseininputoffsetvoltagemayoccuronthenegativevoltageswingandfinallyreachanactivecurrentlimitonbothpositiveandnegativeswings.
PrecautionsshouldbetakentoensurethatthepowersupplyfortheintegratedcircuitneverbecomesreversedinpolarityorthattheunitisnotinadvertentlyinstalledbackwardsinasocketasanunlimitedcurrentsurgethroughtheresultingforwarddiodewithintheICcouldcausefusingoftheinternalconductorsandresultinadestroyedunit.
Aswithmostamplifiers,careshouldbetakenwithleaddress,componentplacementandsupplydecouplinginordertoensurestability.Forexample,resistorsfromtheoutputtoaninputshouldbeplacedwiththebodyclosetotheinputtominimize“pick-up”andmaximizethefrequencyofthefeed-backpolebyminimizingthecapacitancefromtheinputtoground.
Afeedbackpoleiscreatedwhenthefeedbackaroundanyamplifierisresistive.Theparallelresistanceandcapacitancefromtheinputofthedevice(usuallytheinvertinginput)toACgroundsetthefrequencyofthepole.Inmanyinstancesthefrequencyofthispoleismuchgreaterthantheexpected3dBfrequencyoftheclosedloopgainandconsequentlythereisnegligibleeffectonstabilitymargin.However,ifthefeedbackpoleislessthanapproximately6timestheex-pected3dBfrequency,aleadcapacitorshouldbeplaced
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ApplicationHints
(Continued)
fromtheoutputtotheinputoftheopamp.ThevalueoftheaddedcapacitorshouldbesuchthattheRCtimeconstantofthiscapacitorandtheresistanceitparallelsisgreaterthanorequaltotheoriginalfeedbackpoletimeconstant.
TypicalApplications
HighSpeedCurrentBooster
DS005655-9
PNP=2N2905
NPN=2N2219unlessnotedTO-5heatsinksforQ6-Q7
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TypicalApplications
(Continued)
10-BitLinearDACwithNoVOSAdjust
DS005655-32
whereAN=1iftheANdigitalinputishigh
AN=0iftheANdigitalinputislow
SingleSupplyAnalogSwitchwithBufferedOutput
DS005655-33
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DetailedSchematic
DS005655-34
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PhysicalDimensions
inches(millimeters)unlessotherwisenoted
MetalCanPackage(H)
OrderNumberLF411MH/883orLF411ACH
NSPackageNumberH08A
CeramicDual-In-LinePackage(J)OrderNumberLF411MJ/883NSPackageNumberJ08A
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LF411LowOffset,LowDriftJFETInputOperationalAmplifierPhysicalDimensions
inches(millimeters)unlessotherwisenoted(Continued)
MoldedDual-In-LinePackage(N)OrderNumberLF411ACNorLF411CN
NSPackageNumberN08E
LIFESUPPORTPOLICY
NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTOFNATIONALSEMICONDUCTORCORPORATION.Asusedherein:1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser.
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Tel:1-800-272-9959Fax:1-800-737-7018Email:support@nsc.com
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2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.
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Tel:81-3-5639-7560Fax:81-3-5639-7507
Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.
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