Product Order Technical Tools & Support & Folder Now Documents Software Community LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 LM4051-N Precision Micropower Shunt Voltage Reference 1 Features 3 Description • NoOutputCapacitorRequired Ideal for space critical applications, the LM4051-N 1 precision voltage reference is available in the sub- • ToleratesCapacitiveLoads miniature (3 mm x 1.3 mm) SOT-23 surface-mount • ReverseBreakdownVoltageOptionsof1.225V package. The LM4051-N’s advanced design andAdjustable eliminates the need for an external stabilizing • KeySpecifications: capacitor while ensuring stability with any capacitive load, thus making the LM4051-N easy to use. Further – OutputVoltageTolerance(AGrade,25 ̊C)± reducing design effort is the availability of a fixed 0.1%(Maximum) (1.225V) and adjust- able reverse breakdown voltage. – OutputNoise(10Hzto10kHz)20 μVrms The minimum operating current is 60 μA for the – OperatingCurrentRange:60 μAto12mA LM4051-1.2 and the LM4051-ADJ. Both versions haveamaximumoperatingcurrentof12mA. – IndustrialTemp.Range: −40̊Cto+85̊C The LM4051-N comes in three grades (A, B, and C). – ExtendedTemp.Range: −40̊Cto+125 ̊C Thebestgradedevices(A)haveaninitialaccuracyof – TemperatureCoefficient:50ppm/ ̊C 0.1%, while the B-grade have 0.2% and the C-grade (Maximum) 0.5%, all with a tempco of 50 ppm/ ̊C guaranteed from −40̊Cto125 ̊C. 2 Applications The LM4051-N utilizes fuse and zener-zap trim of • Portable,Battery-PoweredEquipment reference voltage during wafer sort to ensure that the • DataAcquisitionSystems prime parts have an accuracy of better than ± 0.1% (Agrade)at25̊C. • Instrumentation • ProcessControl DeviceInformation(1) • EnergyManagement PARTNUMBER PACKAGE BODYSIZE(NOM) • AutomotiveandIndustrial LM4051-N SOT-23(3) 3.00mmx1.30mm • PrecisionAudioComponents (1) For all available packages, see the orderable addendum at • BaseStations theendofthedatasheet. • BatteryChargers • MedicalEquipment • Communication 1.2V SimplifiedSchematic AdjustableReferenceSimplifiedSchematic REF V V DD DD R R S V = 1.225 V S V = ADJ OUT OUT Anode R 1 LM4051-1.2 LM4051-ADJ Cathode R 2 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com Table of Contents 1 Features.................................................................. 1 8.3 FeatureDescription.................................................10 2 Applications........................................................... 1 8.4 DeviceFunctionalModes........................................10 3 Description............................................................. 1 9 ApplicationandImplementation........................ 11 4 RevisionHistory..................................................... 2 9.1 ApplicationInformation............................................11 9.2 TypicalApplications................................................12 5 PinConfigurationandFunctions......................... 3 9.3 SystemExamples...................................................14 6 Specifications......................................................... 3 10 PowerSupplyRecommendations..................... 18 6.1 AbsoluteMaximumRatings......................................3 11 Layout................................................................... 18 6.2 ESDRatings..............................................................3 6.3 RecommendedOperatingConditions.......................4 11.1 LayoutGuidelines.................................................18 6.4 ThermalInformation..................................................4 11.2 LayoutExample....................................................18 6.5 LM4051-1.2ElectricalCharacteristics......................4 12 DeviceandDocumentationSupport................. 19 6.6 LM4051-ADJElectricalCharacteristics.....................5 12.1 ReceivingNotificationofDocumentationUpdates19 6.7 TypicalCharacteristics..............................................7 12.2 CommunityResources..........................................19 7 ParameterMeasurementInformation..................9 12.3 Trademarks...........................................................19 12.4 ElectrostaticDischargeCaution............................19 8 DetailedDescription............................................ 10 12.5 Glossary................................................................19 8.1 Overview.................................................................10 13 Mechanical,Packaging,andOrderable 8.2 FunctionalBlockDiagram.......................................10 Information........................................................... 19 4 Revision History NOTE:Pagenumbersforpreviousrevisionsmaydifferfrompagenumbersinthecurrentversion. ChangesfromRevisionC(March2005)toRevisionD Page • AddedDeviceInformationtable,DeviceComparisontable,ESDRatingstable,FeatureDescriptionsection,Device FunctionalModes,ApplicationandImplementationsection,PowerSupplyRecommendationssection,Layout section,DeviceandDocumentationSupportsection,andMechanical,Packaging,andOrderableInformationsection......1 2 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 5 Pin Configuration and Functions DBZPackage DBZPackage 1.2-V,3-PinSOT-23 Adjustable,3-PinSOT-23 TopView TopView *Thispinmustbeleftfloatingorconnected topin2. PinFunctions PIN I/O DESCRIPTION NAME 1.2V ADJ Anode 2 3 O ShuntCurrent/Voltageinput Cathode 1 2 I/O Commonpin,normallyconnectedtoground NC 3 - - Mustfloatorconnecttoanode FB - 1 I Thresholdrelativetocathode 6 Specifications 6.1 Absolute Maximum Ratings overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1) MIN MAX UNIT Reversecurrent 20 mA Forwardcurrent 10 mA Maximumoutputvoltage(LM4051-ADJ) 15 V Powerdissipation(T =25°C)(2)M3package 280 mW A Vaporphase(60seconds) 215 LeadtemperatureM3packages °C Infrared(15seconds) 220 Storagetemperature,T –65 150 °C stg (1) StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratings only,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommended OperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. (2) ThemaximumpowerdissipationmustbederatedatelevatedtemperaturesandisdictatedbyT (maximumjunctiontemperature), Jmax θ (junctiontoambientthermalresistance),andT (ambienttemperature).Themaximumallowablepowerdissipationatany JA A temperatureisP =(T −T )/θ orthenumbergivenintheAbsoluteMaximumRatings,whicheverislower.FortheLM4051-N, Dmax Jmax A JA T =125°̊C,andthetypicalthermalresistance(θ ),whenboardmounted,is280°C/WfortheSOT-23package. Jmax JA 6.2 ESD Ratings VALUE UNIT Human-bodymodel(HBM),perANSI/ESDA/JEDECJS-001(1)(2) ±2000 V Electrostaticdischarge V (ESD) Machinemodel(MM)(3) 200 (1) JEDECdocumentJEP155statesthat500-VHBMallowssafemanufacturingwithastandardESDcontrolprocess. (2) Thehumanbodymodelisa100-pFcapacitordischargedthrougha1.5-kΩresistorintoeachpin. (3) Themachinemodelisa200-pFcapacitordischargeddirectlyintoeachpin. Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com 6.3 Recommended Operating Conditions overoperatingfree-airtemperaturerange(unlessotherwisenoted) MIN NOM MAX UNIT Industrialtemperature –40 85 Temperature(T ≤T ≤T ) °C min A max Extendedtemperature –40 125 LM4051-1.2 0.06 12 Reversecurrent mA LM4051-ADJ 0.06 12 Outputvoltage LM4051-ADJ 1.24 10 V 6.4 Thermal Information LM4051-ADJ, LM4051-1.2V THERMALMETRIC(1) UNIT DBZ 3PINS R Junction-to-ambientthermalresistance 214.7 °C/W θJA R Junction-to-case(top)thermalresistance 76.4 °C/W θJC(top) R Junction-to-boardthermalresistance 41.3 °C/W θJB ψ Junction-to-topcharacterizationparameter 2.0 °C/W JT ψ Junction-to-boardcharacterizationparameter 40.9 °C/W JB (1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheSemiconductorandICPackageThermalMetricsapplication report. 6.5 LM4051-1.2 Electrical Characteristics overoperatingfree-airtemperaturerange(unlessotherwisenoted) PARAMETER TESTCONDITIONS MIN TYP MAX UNIT ReverseBreakdown I =100μA 1.225 V Voltage R LM4051AIM3(2) ±1.2 I =100μA LM4051BIM3LM4051BEM3(2) ±2.4 R LM4051CIM3(2) ±6 V R ReverseBreakdown LM4051AIM3(2) ±5.2(1) VoltageTolerance(1) IndustrialTemp.Range LM4051BIM3 (2) ±6.4(1) mV T =T =T toT A J MIN MAX LM4051CIM3(2) ±10.1(1) ExtendedTemp.Range LM4051BEM3(2) ±8.6(1) T =T =T toT A J MIN MAX T =25°C 39 J IndustrialTemp.Range µA MinimumOperating 65 I T =T =T toT RMIN Current A J MIN MAX ExtendedTemp.Range 70 T =T =T toT A J MIN MAX (1) ThisovertemperaturelimitforReverseBreakdownVoltageToleranceisdefinedastheroomtemperatureReverseBreakdownVoltage Tolerance±[(∆VR/∆T)(max∆T)(VR)].Where,∆VR/∆TistheVRtemperaturecoefficient,max∆Tisthemaximumdifferencein temperaturefromthereferencepointof25°̊CtoTMAXorTMIN,andVRisthereversebreakdownvoltage.Thetotalovertemperature toleranceforthedifferentgradesintheindustrialtemperaturerangewheremax∆T=65̊Cisshownbelow: (a) A-grade:±0.425%=±0.1%±50ppm/°̊Cx65°̊C (b) B-grade:±0.525%=±0.2%±50ppm/°̊Cx65°̊C (c) C-grade:±0.825%=±0.5%±50ppm/°̊Cx65°̊C Therefore,asanexample,theA-gradeLM4051-1.2hasanover-temperatureReverseBreakdownVoltagetoleranceof±1.2Vx0.425% =±5.2mV. (2) Limitsare100%productiontestedat25̊C.LimitsovertemperatureareguaranteedthroughcorrelationusingStatisticalQualityControl (SQC)methods.ThelimitsareusedtocalculateNational’sAOQL. 4 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 LM4051-1.2 Electrical Characteristics (continued) overoperatingfree-airtemperaturerange(unlessotherwisenoted) PARAMETER TESTCONDITIONS MIN TYP MAX UNIT I =10mA ±20 R AverageReverse BreakdownVoltage IR=1mA ±15 ∆V /∆T ppm/̊C R TCeomefpfiecireantut(r1e) IR=100μA TJ=25°C ±15 ∆T=−40̊Cto125̊C T =T =T toT ±50(1) A J MIN MAX T =25°C 0.3 J IndustrialTemp.Range 1.1(1) I ≤I ≤1mA T =T =T toT ReverseBreakdown RMIN R A J MIN MAX ∆V /∆I VoltageChangewith ExtendedTemp.Range 1.5(1) mV R R OperatingCurrent T =T =T toT A J MIN MAX Change T =25°C 1.8 J IndustrialTemp.Range 6(1) 1mA≤I ≤12mA T =T =T toT R A J MIN MAX ExtendedTemp.Range 8(1) T =T =T toT A J MIN MAX ReverseDynamic Z I =1mA,f=120Hz 0.5 Ω R Impedance R I =100μA e WidebandNoise R 20 μVrms N 10Hz≤f≤10kHz ReverseBreakdown ∆V VoltageLongTerm t=1000hrs,T=25̊C±0.1̊C,I =100μA 120 ppm R R Stability(3) V ThermalHysteresis(4) ∆T=−40̊Cto125̊C 0.36 mV/V HYST (3) Long-termstabilityisV at25°̊Cmeasuredduring1000hrs. R (4) Thermalhysteresisisdefinedasthedifferenceinvoltagemeasuredat+25̊Caftercyclingtotemperature–40̊Candthe25̊C measurementaftercyclingtotemperature+125̊C. 6.6 LM4051-ADJ Electrical Characteristics overoperatingfree-airtemperaturerange(unlessotherwisenoted) PARAMETER TESTCONDITIONS MIN TYP MAX UNIT ReferenceVoltage I =100μA,V =5V 1.212 V R OUT LM4051AIM3(3) ±1.2 I =100μA,V =5V LM4051BIM3(3) ±2.4 R OUT VREF ReferenceVoltage LM4051CIM3(3) ±6 Tolerance(1)(2) LM4051AIM3(3) ±5.2 mV IndustrialTemp.Range LM4051BIM3(3) ±6.4 T =T =T toT A J MIN MAX LM4051CIM3(3) ±10.1 (1) ThisovertemperaturelimitforReverseBreakdownVoltageToleranceisdefinedastheroomtemperatureReverseBreakdownVoltage Tolerance±[(∆V /∆T)(max∆T)(V )].Where,∆V /∆TistheV temperaturecoefficient,max∆Tisthemaximumdifferenceintemperature R R R R fromthereferencepointof25°̊CtoT orT ,andV isthereversebreakdownvoltage.Thetotalovertemperaturetoleranceforthe MAX MIN R differentgradesintheindustrialtemperaturerangewheremax∆T=65̊Cisshownbelow: (a) A-grade:±0.425%=±0.1%±50ppm/°̊C×65°̊C (b) B-grade:±0.525%=±0.2%±50ppm/°̊C×65°̊C (c) C-grade:±0.825%=±0.5%±50ppm/°̊C×65°̊C Therefore,asanexample,theA-gradeLM4051-1.2hasanovertemperatureReverseBreakdownVoltagetoleranceof±1.2V×0.425% =±5.2mV. (2) Referencevoltageandtemperaturecoefficientwillchangewithoutputvoltage.SeeTypicalCharacteristicscurves. (3) Limitsare100%productiontestedat25̊C.LimitsovertemperatureareensuredthroughcorrelationusingStatisticalQualityControl (SQC)methods.ThelimitsareusedtocalculateNational’sAOQL. Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com LM4051-ADJ Electrical Characteristics (continued) overoperatingfree-airtemperaturerange(unlessotherwisenoted) PARAMETER TESTCONDITIONS MIN TYP MAX UNIT LM4051AIM3(4) 36 LM4051BIM3(4) 36 MinimumOperating LM4051CIM3(4) 36 I µA RMIN Current LM4051AIM3(3) 60 IndustrialTemp.Range LM4051BIM3(3) 60 T =T =T toT A J MIN MAX LM4051CIM3 (3) 65 T =25°C 0.3 J I ≤I ≤1mA ∆VREF RCehfaenrgeencweitVhoOltapgeerating VROMUINT≥1R.6V(5) ITnAdu=sTtrJia=lTTeMmINpt.oRTaMnAgXe 1.1(1) mV /∆IR CurrentChange TJ=25°C 0.6 1mA≤I ≤12mA R VOUT≥1.6V(5) IndustrialTemp.Range 6(1) T =T =T toT A J MIN MAX ReferenceVoltage TJ=25°C –1.69 ∆V /∆VROEF CVohlatanggeeCwhitahnOgeutput IR=0.1mA ITndu=sTtria=lTTempt.oRTange –2.8(1) mV A J MIN MAX I FeedbackCurrent 70 130 nA FB T =25°C 20 J IR=10mA IndustrialTemp.Range ±50(1) T =T =T toT A J MIN MAX AverageReference TJ=25°C 15 ∆/∆VTREF VCooletaffgiceieTnetm(Npoetreat8u)re V∆TOU=T−=420.5̊CVto+125̊C IR=1mA ITndu=sTtria=lTTempt.oRTange ±50(1) ppm/°C A J MIN MAX T =25°C 15 J IR=100μA IndustrialTemp.Range ±50(1) T =T =T toT A J MIN MAX Z DynamicOutput IR=1mA,f=120Hz, VOUT=VREF 0.3 Ω OUT Impedance IAC=0.1IR VOUT=10V 2 e WidebandNoise I =100μA,V =V ,10Hz≤f≤10kHz 20 µVrms N R OUT REF ReferenceVoltageLong ∆VREF TermStability(6) t=1000hrs,IR=100μA,T=25̊C±0.1̊C 120 ppm V ThermalHysteresis(7) ∆T=−40̊Cto+125̊C 0.3 mV/V HYST (4) Limitsare100%productiontestedat25̊C.LimitsovertemperatureareguaranteedthroughcorrelationusingStatisticalQualityControl (SQC)methods.ThelimitsareusedtocalculateNational’sAOQL. (5) WhenV ≤1.6V,theLM4051-ADJintheSOT-23packagemustoperateatreducedI .Thisiscausedbytheseriesresistanceofthe OUT R dieattachbetweenthedie(–)outputandthepackage(–)outputpin.SeetheOutputSaturationcurveintheTypicalCharacteristics section. (6) Long-termstabilityisV at25°̊Cmeasuredduring1000hrs. R (7) Thermalhysteresisisdefinedasthedifferenceinvoltagemeasuredat+25̊Caftercyclingtotemperature–40̊Candthe25̊C measurementaftercyclingtotemperature+125̊C. 6 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 6.7 Typical Characteristics Figure1.TemperatureDriftforDifferentAverage Figure2.OutputImpedancevsFrequency TemperatureCoefficient Figure3.NoiseVoltage Figure4.ReverseCharacteristicsandMinimumOperating Current Figure5.Start-UpCharacteristics Figure6.ReferenceVoltagevsOutputVoltageand Temperature Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com Typical Characteristics (continued) Figure7.ReferenceVoltagevsTemperatureandOutput Figure8.FeedbackCurrentvsOutputVoltageand Voltage Temperature Figure9.OutputSaturation(SOT-23Only) Figure10.OutputImpedancevsFrequency Figure11.OutputImpedancevsFrequency Figure12.ReverseCharacteristics 8 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 Typical Characteristics (continued) Figure13.LargeSignalResponse Figure14.ThermalHysteresis 7 Parameter Measurement Information Figure15. TestCircuitforStart-UpCharacteristics Figure16. TestCircuitforReverseCharacteristics Figure17. TestCircuitforLargeSignalResponse Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com 8 Detailed Description 8.1 Overview The LM4051-N is a precision voltage reference available in SOT-23 surface mount package. The LM4051-N is available in a 1.225 V fixed-option as well as an adjustable voltage option. The LM4051-N comes in three different tolerance grades (A, B, and C). The best grade devices (A) have an initial accuracy of 0.1%, while the B-grade have 0.2% and the C-grade 0.5%, all with a temperature coefficient of 50 ppm/˚C guaranteed from −40˚Cto125˚C. 8.2 Functional Block Diagram *LM4051-ADJonly **LM4051-1.2only 8.3 Feature Description The LM4051-N device is effectively a precision Zener diode. The part requires a small quiescent current for regulation, and regulates the output voltage by shunting more or less current to ground, depending on input voltage and load. The only external component requirement is a resistor between the cathode and the input voltagetosettheinputcurrent.Anexternalcapacitorcanbeusedontheinputoroutput,butisnotrequired. For the adjustable verson, feedback is applied from the Cathode and Reference pins, the LM4051-N behaves as aZenerdiode,regulatingtoaconstantvoltagedependentoncurrentbeingsuppliedintothecathode.Thisisdue totheinternalamplifierandreferenceenteringtheproperoperatingregions.Thesameamountofcurrentneeded in the above feedback situation must be applied to this device in open loop, servo or error amplifying implementationsinorderforittobeintheproperlinearregiongivingtheLM4051-Nenoughgain. 8.4 Device Functional Modes 8.4.1 LM4051-N-1.2V The LM4051-N - 1.2V device is a fixed output voltage part, where the feedback is internal. Therefore, the part can only operate is a closed loop mode and the output voltage cannot be adjusted. The output voltage will remain in regulation as long as IR is between IRMIN. Proper selection of the external resistor for input voltage rangeandloadcurrentrangewillensuretheseconditionsaremet. 8.4.2 LM4051-N-ADJ ThemajorityofapplicationsinvolvingLM4051-Nusesclosedloopoperationtoregulateafixedvoltageorcurrent. The feedback enables this device to behave as an error amplifier, computing a portion of the output voltage and adjusting it to maintain the desired regulation. This is done by relating the output voltage back to the reference pin in a manner to make it equal to the internal reference voltage, which can be accomplished via resistive or directfeedback. 10 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validateandtesttheirdesignimplementationtoconfirmsystemfunctionality. 9.1 Application Information The LM4051-N is a precision micro-power curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4051-N is available in the sub-miniature SOT-23 surface-mount package. The LM4051-N has been designed for stable operation without the need of an external capacitor connected between the “+” pin and the “−” pin. If, however, a bypass capacitor is used, the LM4051-N remains stable. Design effort is further reduced with the choice of either a fixed 1.2-V or an adjustable reverse breakdown voltage. The minimum operating current is 60 μA for the LM4051-1.2 and the LM4051-ADJ. Both versions have a maximum operatingcurrentof12mA. LM4051-N's using the SOT-23 package have pin 3 connected as the (–) output through the package’s die attach interface. Therefore, the LM4051-1.2’s pin 3 must be left floating or connected to pin 2 and the LM4051-ADJ’s pin3isthe(–)output. The typical thermal hysteresis specification is defined as the change in +25 ̊C voltage measured after thermal cycling. The device is thermal cycled to temperature –40 ̊C and then measured at 25 ̊C. Next the device is thermal cycled to temperature +125 ̊C and again measured at 25 ̊C. The resulting V delta shift between the OUT 25 ̊C measurements is thermal hysteresis. Thermal hysteresis is common in precision references and is induced by thermal-mechanical package stress. Changes in environmental storage temperature, operating temperature andboardmountingtemperatureareallfactorsthatcancontributetothermalhysteresis. In a conventional shunt regulator application (Figure 18), an external series resistor (R ) is connected between S the supply voltage and the LM4051-N. R determines the current that flows through the load (I ) and the S L LM4051-N (I ). Since load current and supply voltage may vary, R should be small enough to supply at least Q S the minimum acceptable I to the LM4051-N even when the supply voltage is at its minimum and the load Q current is at its maximum value. When the supply voltage is at its maximum and I is at its minimum, R should L S belargeenoughsothatthecurrentflowingthroughtheLM4051-Nislessthan12mA. R should be selected based on the supply voltage, (V ), the desired load and operating current, (I and I ), and S S L Q theLM4051-N'sreversebreakdownvoltage,V . R V -V R = S R S I +I L Q (1) The LM4051-ADJ’s output voltage can be adjusted to any value in the range of 1.24 V through 10 V. It is a function of the internal reference voltage (V ) and the ratio of the external feedback resistors as shown in REF Figure20.TheoutputvoltageisfoundusingEquation2: V = V é(R2 / R1)+1ù O REFë û where • V istheoutputvoltage (2) O V -V R = S R S I +I +I L Q F (3) TheactualvalueoftheinternalV isafunctionofV .ThecorrectedV isdeterminedbyEquation4: REF O REF V = V (DV / DV )+ V REF O REF O Y where • V =1.22V (4) Y Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com Application Information (continued) ∆V /∆V is found in the LM4051-ADJ Electrical Characteristics and is typically −1.55 mV/V. You can get a REF O more accurate indication of the output voltage by replacing the value of V in Equation 2 with the value found REF usingEquation4. 9.2 Typical Applications 9.2.1 ShuntRegulator Figure18. ShuntRegulator 9.2.1.1 DesignRequirements V >V IN OUT SelectR suchthat: S I <I <I whereI =12mA RMIN R RMAX RMAX SeeLM4051-1.2ElectricalCharacteristicsforminimumoperatingcurrentforeachvoltageoptionandgrade. 9.2.1.2 DetailedDesignProcedure The resistor R must be selected such that current, I , will remain in the operational region of the part for the S R entireV rangeandloadcurrentrange.ThetwoextremestoconsiderareV atitsmaximum,andtheloadatits IN IN minimum, where R must be large enough to main I < I . For most desigins, 0.1 mA ≤ I ≤ 1 mA is a good S R RMAX R startingpoint. UsecrossandcrosstosetR betweenR andR . S S_MIN S_MAX V -V R = IN_MAX OUT S_MIN I +I LOAD_MIN R_MAX (5) V -V R = IN_MIN OUT S_MAX I +I LOAD_MAX R_MIN (6) 12 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 Typical Applications (continued) 9.2.1.3 ApplicationCurves Figure19.ReverseCharacteristicsandMinimumOperatingCurrent 9.2.2 AdjustableShuntRegulator Figure20. AdjustableShuntRegulator 9.2.2.1 DesignRequirements V >V IN OUT SelectR suchthat: S I <I <I whereI =12mA RMIN R RMAX RMAX SeeLM4051-ADJElectricalCharacteristicsforminimumoperatingcurrentforeachvoltageoptionandgrade. 9.2.2.2 DetailedDesignProcedure In order to program the cathode voltage to a regulated voltage a resistive bridge must be shunted between the cathode and anode pins with the mid point tied to the reference pin. This can be seen in Figure 20, with R1 & R2 being the resistive bridge. The cathode/output voltage in the shunt regulator configuration can be approximated by the equation shown in Equation 7. The cathode voltage can be more accurately determined by taking in to accountthecathodecurrentshowninequationEquation8. § R1• V =¤1+ ‚×V O ' R2„ REF (7) § R1• V = 1+ ×(cid:11)V (cid:16)I ×R (cid:12) ¤ ‚ O ' R2„ REF REF 1 (8) Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com Typical Applications (continued) In order for this equation to be valid, LM4051-ADJ must be fully biased so that it has enough open loop gain to mitigateanygainerror.ThiscanbedonebemeetingtheI denotedinLM4051-ADJElectricalCharacteristics. RMIN 9.3 System Examples Figure21. BoundedAmplifierReducesSaturation-inducedDelaysandCanPreventSucceedingStage Damage.NominalClampingVoltageis ±V (LM4051-N'sReverseBreakdownVoltage)+2DiodeV . O F Figure22. VoltageLevelDetector Figure23. VoltageLevelDetector 14 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 System Examples (continued) Figure24. FastPositiveClamp2.4V+V D1 Figure25. BidirectionalClamp ± 2.4V Figure26. BidirectionalAdjustableClamp ± 18Vto± 2.4V Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com System Examples (continued) Figure27. BidirectionalAdjustableClamp ± 2.4Vto ± 6V Figure28. SimpleFloatingCurrentDetector *D1canbeanyLED,V =1.5Vto2.2Vat3mA.D1mayactasanindicator.D1willbeonifI fallsbelow F THRESHOLD thethresholdcurrent,exceptwithI=O. Figure29. CurrentSource 16 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 System Examples (continued) Figure30. PrecisionFloatingCurrentDetector Figure31. Precision1μAto1mACurrentSource Figure32. Precision1μAto1mACurrentSource Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LM4051-N

LM4051-N SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 www.ti.com 10 Power Supply Recommendations While a bypass capacitor is not required on the input voltage line, TI recommends reducing noise on the input whichcouldaffecttheoutput.A0.1-µFceramiccapacitororlargerisrecommended. In order to not exceed the maximum cathode current, be sure that the supply current is limited. For applications shunting high currents, pay attention to the cathode and anode trace lengths, adjusting the width of the traces to havepropercurrentdensity. 11 Layout 11.1 Layout Guidelines Bypass capacitors should be placed as close to the device as possible. Current-carrying traces need to have widths appropriate for the amount of current they are carrying. Place R as close as possible to the cathode. S Althoughnotascritical,keepfeedbackresistorclosetothedevicewheneverpossible. 11.2 Layout Example R physically close to device cathode S R S C C IN OUT C physically C physically IN OUT close to device close to device Figure33. LayoutDiagram RSphysically close to device cathode CINphysically close to device COUTphysically close to device Figure34. FeedbackResistorsLayoutDiagram 18 SubmitDocumentationFeedback Copyright©2000–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM4051-N

LM4051-N www.ti.com SNOS491D–FEBRUARY2000–REVISEDSEPTEMBER2018 12 Device and Documentation Support 12.1 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed.Forchangedetails,reviewtherevisionhistoryincludedinanyreviseddocument. 12.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TIE2E™OnlineCommunity TI'sEngineer-to-Engineer(E2E)Community.Createdtofostercollaboration amongengineers.Ate2e.ti.com,youcanaskquestions,shareknowledge,exploreideasandhelp solveproblemswithfellowengineers. DesignSupport TI'sDesignSupport QuicklyfindhelpfulE2Eforumsalongwithdesignsupporttoolsand contactinformationfortechnicalsupport. 12.3 Trademarks E2EisatrademarkofTexasInstruments. Allothertrademarksarethepropertyoftheirrespectiveowners. 12.4 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriateprecautions.Failuretoobserveproperhandlingandinstallationprocedurescancausedamage. ESDdamagecanrangefromsubtleperformancedegradationtocompletedevicefailure.Precisionintegratedcircuitsmaybemore susceptibletodamagebecauseverysmallparametricchangescouldcausethedevicenottomeetitspublishedspecifications. 12.5 Glossary SLYZ022—TIGlossary. Thisglossarylistsandexplainsterms,acronyms,anddefinitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of thisdocument.Forbrowser-basedversionsofthisdatasheet,refertotheleft-handnavigation. Table1.SOT-23PackageMarkingInformation PARTMARKING FIELDDEFINITION RHA RIA ThirdField: SecondField: A-C=InitialReservedBreakdown RHB FirstField: H=1.225-VVoltageOption VoltageorReferenceVoltage RIB R=Reference I=Adjustable Tolerance RHC A=±0.1%,B=±0.2%,C=±0.5% RIC Copyright©2000–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:LM4051-N

IMPORTANTNOTICEANDDISCLAIMER TIPROVIDESTECHNICALANDRELIABILITYDATA(INCLUDINGDATASHEETS),DESIGNRESOURCES(INCLUDINGREFERENCE DESIGNS),APPLICATIONOROTHERDESIGNADVICE,WEBTOOLS,SAFETYINFORMATION,ANDOTHERRESOURCES“ASIS” ANDWITHALLFAULTS,ANDDISCLAIMSALLWARRANTIES,EXPRESSANDIMPLIED,INCLUDINGWITHOUTLIMITATIONANY IMPLIEDWARRANTIESOFMERCHANTABILITY,FITNESSFORAPARTICULARPURPOSEORNON-INFRINGEMENTOFTHIRD PARTYINTELLECTUALPROPERTYRIGHTS. TheseresourcesareintendedforskilleddevelopersdesigningwithTIproducts.Youaresolelyresponsiblefor(1)selectingtheappropriate TIproductsforyourapplication,(2)designing,validatingandtestingyourapplication,and(3)ensuringyourapplicationmeetsapplicable standards,andanyothersafety,security,orotherrequirements.Theseresourcesaresubjecttochangewithoutnotice.TIgrantsyou permissiontousetheseresourcesonlyfordevelopmentofanapplicationthatusestheTIproductsdescribedintheresource.Other reproductionanddisplayoftheseresourcesisprohibited.NolicenseisgrantedtoanyotherTIintellectualpropertyrightortoanythird partyintellectualpropertyright.TIdisclaimsresponsibilityfor,andyouwillfullyindemnifyTIanditsrepresentativesagainst,anyclaims, damages,costs,losses,andliabilitiesarisingoutofyouruseoftheseresources. TI’sproductsareprovidedsubjecttoTI’sTermsofSale(www.ti.com/legal/termsofsale.html)orotherapplicabletermsavailableeitheron ti.comorprovidedinconjunctionwithsuchTIproducts.TI’sprovisionoftheseresourcesdoesnotexpandorotherwisealterTI’sapplicable warrantiesorwarrantydisclaimersforTIproducts. MailingAddress:TexasInstruments,PostOfficeBox655303,Dallas,Texas75265 Copyright©2018,TexasInstrumentsIncorporated