LM78M12中⽂资料LM341/LM78MXX Series3-Terminal Positive Voltage RegulatorsGeneral DescriptionThe LM341and LM78MXX series of three-terminal positive voltage regulators employ built-in current limiting,thermal shutdown,and safe-operating area protection which makes them virtually immune to damage from output overloads.With adequate heatsinking,they can deliver in excess of 0.5A output current.Typical applications would include local (on-card)regulators which can eliminate the noise and de-graded performance associated with single-point regulation.Featuresn Output current in excess of 0.5A n No external componentsn Internal thermal overload protection n Internal short circuit current-limitingn Output transistor safe-area compensationnAvailable in TO-220,TO-39,and TO-252D-PAK packagesn Output voltages of 5V,12V,and 15VConnection DiagramsTO-39Metal Can Package (H)DS010484-5Bottom ViewOrder Number LM78M05CH,LM78M12CH or LM78M15CHSee NS Package Number H03ATO-220Power Package (T)DS010484-6Top ViewOrder Number LM341T-5.0,LM341T-12,LM341T-15,LM78M05CT,LM78M12CT or LM78M15CTSee NS Package Number T03BTO-252DS010484-19Top ViewOrder Number LM78M05CDT See NS Package Number TD03BJuly 1999LM341/LM78MXX Series 3-Terminal Positive Voltage Regulators1999National Semiconductor Corporation /doc/96ef4d46852458fb770b5641.htmlAbsolute Maximum Ratings(Note1)If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.Lead Temperature(Soldering,10seconds)TO-39Package(H)300?C TO-220Package(T)260?C Storage Temperature Range?65?C to+150?C Operating Junction TemperatureRange?40?C to+125?C Power Dissipation(Note2)Internally Limited Input Voltage5V≤V O≤15V35V ESD Susceptibility TBDElectrical CharacteristicsLimits in standard typeface are for T J=25?C,and limits in boldface type apply over the?40?C to+125?C operating temperature range.Limits are guaranteed by production testing or correlation techniques using standard Statistical Quality Control(SQC) methods.LM341-5.0,LM78M05CUnless otherwise specified:V IN=10V,C IN=0.33µF,C O=0.1µFSymbol Parameter Conditions Min Typ Max Units V O Output Voltage I L=500mA 4.8 5.0 5.2V5mA≤I L≤500mA 4.75 5.0 5.25P D≤7.5W,7.5V≤V IN≤20VV R LINE Line Regulation7.2V≤V IN≤25V I L=100mA50mVI L=500mA100V R LOAD Load Regulation5mA≤I L≤500mA100I Q Quiescent Current I L=500mA410.0mA ?I Q Quiescent Current Change5mA≤I L≤500mA0.57.5V≤V IN≤25V,I L=500mA 1.0V n Output Noise Voltage f=10Hz to100kHz40µVElectrical CharacteristicsLimits in standard typeface are for T J=25?C,and limits in boldface type apply over the?40?C to+125?C operating temperature range.Limits are guaranteed by production testing or correlation techniques using standard Statistical Quality Control(SQC) methods.(Continued)LM341-12,LM78M12CUnless otherwise specified:V IN=19V,C IN=0.33µF,C O=0.1µFSymbol Parameter Conditions Min Typ Max UnitsV O Output Voltage I L=500mA11.51212.5V5mA≤I L≤500mA11.41212.6P D≤7.5W,14.8V≤V IN≤27VV R LINE Line Regulation14.5V≤V IN≤30V I L=100mA120mVI L=500mA240V R LOAD Load Regulation5mA≤I L≤500mA240I Q Quiescent Current I L=500mA410.0mAI Q Quiescent Current Change5mA≤I L≤500mA0.514.8V≤V IN≤30V,I L=500mA 1.0V n Output Noise Voltage f=10Hz to100kHz75µVRipple Rejection f=120Hz,I L=500mA69dBV IN Input Voltage Required I L=500mA17.6V to Maintain Line RegulationV O Long Term Stability I L=500mA60mV/khrs Note1:Absolute maximum ratings indicate limits beyond which damage to the component may occur.Electrical specifications do not apply when operating the de-vice outside of its rated operating conditions.Note2:The typical thermal resistance of the three package types is:T(TO-220)package:θ(JA)=60?C/W,θ(JC)=5?C/WH(TO-39)package:θ(JA)=120?C/W,θ(JC)=18?C/WDT(TO-252)package:θ(JA)=92?C/W,θ(JC)=10?C/W3/doc/96ef4d46852458fb770b5641.htmlSchematic DiagramDS010484-1 /doc/96ef4d46852458fb770b5641.html 4 Typical Performance CharacteristicsPeak Output CurrentDS010484-10Ripple RejectionDS010484-11Ripple RejectionDS010484-12Dropout VoltageDS010484-13Output Voltage(Normalizedto1V at T J=25?C)DS010484-14Quiescent CurrentDS010484-15/doc/96ef4d46852458fb770b5641.html 5Typical Performance Characteristics(Continued)Design ConsiderationsThe LM78MXX/LM341XX fixed voltage regulator series has built-in thermal overload protection which prevents the de-vice from being damaged due to excessive junction tem-perature.The regulators also contain internal short-circuit protection which limits the maximum output current,and safe-area pro-tection for the pass transistor which reduces the short-circuit current as the voltage across the pass transistor is in-creased.Although the internal power dissipation is automatically lim-ited,the maximum junction temperature of the device must be kept below +125?C in order to meet data sheet specifica-tions.An adequate heatsink should be provided to assure this limit is not exceeded under worst-case operating condi-tions (maximum input voltage and load current)if reliable performance is to be obtained).1.0Heatsink ConsiderationsWhen an integrated circuit operates with appreciable cur-rent,its junction temperature is elevated.It is important to quantify its thermal limits in order to achieve acceptable per-formance and reliability.This limit is determined by summing the individual parts consisting of a series of temperature rises from the semiconductor junction to the operating envi-ronment.A one-dimension steady-state model of conduction heat transfer is demonstrated in The heat generated at thedevice junction flows through the die to the die attach pad,through the lead frame to the surrounding case material,to the printed circuit board,and eventually to the ambient envi-ronment.Below is a list of variables that may affect the ther-mal resistance and in turn the need for a heatsink.R θJC (Component Variables)R θCA (Application Variables)Leadframe Size &Material Mounting Pad Size,Material,&LocationNo.of Conduction Pins Placement of Mounting Pad Die SizePCB Size &Material Die Attach MaterialTraces Length &WidthMolding Compound Size and MaterialAdjacent Heat Sources Volume of Air Air FlowAmbient Temperature Shape of Mounting PadQuiescent CurrentDS010484-16Output ImpedanceDS010484-17Line Transient Response DS010484-7Load Transient ResponseDS010484-8/doc/96ef4d46852458fb770b5641.html6Design Considerations(Continued)The LM78MXX/LM341XX regulators have internal thermal shutdown to protect the device from over-heating.Under all possible operating conditions,the junction temperature of the LM78MXX/LM341XX must be within the range of 0?C to 125?C.A heatsink may be required depending on the maxi-mum power dissipation and maximum ambient temperature of the application.To determine if a heatsink is needed,the power dissipated by the regulator,P D ,must be calculated:I IN =I L +I GP D =(V IN ?V OUT )I L +V IN I Gshows the voltages and currents which are present in the circuit.The next parameter which must be calculated is the maxi-mum allowable temperature rise,T R (max):θJA =TR (max)/P D If the maximum allowable value for θJA ?C/w is found to be ≥60?C/W for TO-220package or ≥92?C/W for TO-252pack-age,no heatsink is needed since the package alone will dis-sipate enough heat to satisfy these requirements.If the cal-culated value for θJA fall below these limits,a heatsink is required.As a design aid,Table 1shows the value of the θJA of TO-252for different heatsink area.The copper patterns that we used to measure these θJA are shown at the end of the Application Note Section.reflects the same test results as what are in the Table 1shows the maximum allowable power dissipation vs.ambi-ent temperature for theTO-252device.shows the maximum allowable power dissipation vs.copper area (in 2)for the TO-252device.Please see AN1028for power enhancement techniques to be used with TO-252package.TABLE 1.θJA Different Heatsink AreaLayoutCopper AreaThermal Resistance Top Sice (in 2)*Bottom Side (in 2)(θJA ,?C/W)TO-25210.0123010320.06608730.306040.5305450.7605261047700.284800.470900.6631000.857110157120.0660.06689130.1750.17572140.2840.28461150.3920.39255160.50.553*Tab of device attached to topside copperDS010484-23FIGURE 1.Cross-sectional view of Integrated Circuit Mounted on a printed circuit board.Note that the case temperature is measured at the point where the leadscontact with the mounting pad surface DS010484-24FIGURE 2.Power Dissipation Diagram/doc/96ef4d46852458fb770b5641.html 7Design Considerations(Continued)Typical ApplicationDS010484-20FIGURE 3.θJA vs.2oz Copper Area for TO-252DS010484-22FIGURE 4.Maximum Allowable Power Dissipation vs.Ambient Temperature for TO-252DS010484-21FIGURE 5.Maximum Allowable Power Dissipation vs.2oz.Copper Area for TO-252DS010484-9*Required if regulator input is more than 4inches from input filter capacitor (or if no input filter capacitor is used).**Optional for improved transient response./doc/96ef4d46852458fb770b5641.html 8 Physical Dimensions inches(millimeters)unless otherwise notedTO-39Metal Can Package(H)Order Number LM78M05CH,LM78M12CH or LM78M15CHNS Package Number H03A9/doc/96ef4d46852458fb770b5641.htmlPhysical Dimensions inches(millimeters)unless otherwise noted(Continued)TO-220Power Package(T)Order Number LM341T-5.0,LM341T-12,LM341T-15,LM78M05CT,LM78M12CT or LM78M15CT NS Package Number T03B/doc/96ef4d46852458fb770b5641.html 10Physical Dimensionsinches (millimeters)unless otherwise noted (Continued)LIFE SUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION.As used herein:1.Life support devices or systems are devices or systems which,(a)are intended for surgical implant into the body,or (b)support or sustain life,and whose failure to perform when properly used in accordance with instructions for use provided in the labeling,can be reasonably expected to result in a significant injury to the user.2.A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system,or to affect its safety or effectiveness.National Semiconductor Corporation AmericasTel:1-800-272-9959Fax:1-800-737-7018Email:support@/doc/96ef4d46852458fb770b5641.htmlNational Semiconductor EuropeFax:+49(0)180-5308586Email:europe.support@/doc/96ef4d46852458fb770b5641.htmlDeutsch Tel:+49(0)180-5308585English Tel:+49(0)180-5327832Fran?ais Tel:+49(0)180-5329358Italiano Tel:+49(0)180-5341680National Semiconductor Asia Pacific Customer Response Group Tel:65-2544466Fax:65-2504466Email:sea.support@/doc/96ef4d46852458fb770b5641.htmlNational Semiconductor Japan Ltd.Tel:81-3-5639-7560Fax:81-3-5639-7507/doc/96ef4d46852458fb770b5641.htmlTO-252Order Number LM78M05CDT NS Package Number TD03BLM341/LM78MXX Series 3-Terminal Positive Voltage RegulatorsNational does not assume any responsibility for use of any circuitry described,no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry andspecifications.。
