LP3876-ADJGeneral DescriptionFeaturesApplicationsTypical Application CircuitConnection DiagramsPin Description for TO220-5 and TO263-5 PackagesOrdering InformationTABLE 1. Package Marking and Ordering InformationBlock Diagram LP3876-ADJAbsolute Maximum RatingsOperating RatingsElectrical Characteristics LP3876-ADJTypical Performance Characteristics Application HintsSETTING THE OUTPUT VOLTAGETURN-ON CHARACTERISTICS FOR OUTPUT VOLTAGES PROGRAMMED TO 2.0V OR BELOWEXTERNAL CAPACITORSCFF (Feed Forward Capacitor)SELECTING A CAPACITORCAPACITOR CHARACTERISTICSPCB LAYOUTRFI/EMI SUSCEPTIBILITYOUTPUT NOISESHORT-CIRCUIT PROTECTIONSHUTDOWN OPERATIONDROPOUT VOLTAGEREVERSE CURRENT PATHPOWER DISSIPATION/HEATSINKINGHEATSINKING TO-220 PACKAGEHEATSINKING TO-263 PACKAGEFIGURE 1. JA vs Copper (1 Ounce) Area for TO-263 package FIGURE 2. Maximum power dissipation vs ambient temperature for TO-263 package Physical DimensionsLP3876-ADJ3A Fast Ultra Low Dropout Linear RegulatorGeneral DescriptionThe LP3876-ADJ fast ultra low-dropout linear regulators op-erate from a +2.5V to +7.0V input supply. These ultra lowdropout linear regulators respond very quickly to stepchanges in load, which makes them suitable for low voltagemicroprocessor applications. The LP3876-ADJ is developedon a CMOS process which allows low quiescent currentoperation independent of output load current. This CMOSprocess also allows the LP3876-ADJ to operate under ex-tremely low dropout conditions.Dropout Voltage: Ultra low dropout voltage; typically 80mVat 300mA load current and 800mV at 3A load current.Ground Pin Current: Typically 6mA at 3A load current.Shutdown Mode: Typically 1µA quiescent current when theshutdown pin is pulled low.Adjustable Output Voltage: The output voltage may beprogrammed via two external resistors.Featuresn Ultra low dropout voltagen Low ground pin currentn Load regulation of 0.08%n 1µA quiescent current in shutdown moden Guaranteed output current of 3A DCn Available in TO-263 and TO-220 packagesn Minimum output capacitor requirementsn Overtemperature/overcurrent protectionn −40˚C to +125˚C junction temperature rangeApplicationsn Microprocessor power suppliesn GTL, GTL+, BTL, and SSTL bus terminatorsn Power supplies for DSPsn SCSI terminatorn Post regulatorsn High efficiency linear regulatorsn Battery chargersn Other battery powered applicationsTypical Application Circuit20074445*See Application HintsSeptember 2006LP3876-ADJ 3A Fast Ultra Low Dropout Linear Regulator© 2006 National Semiconductor Corporation DS200744 www.national.comConnection Diagrams20074405Top ViewTO220-5 PackageBent, Staggered Leads20074406Top ViewTO263-5 PackagePin Description for TO220-5 and TO263-5 PackagesPin #LP3876-ADJName Function1SDShutdown2VINInput Supply3 GND Ground4VOUTOutput Voltage5 ADJ Set Output VoltageOrdering Information20074431Package Type Designator is "T" for TO220 package, and "S" for TO263 package.TABLE 1. Package Marking and Ordering InformationOutputVoltage Order NumberCurrentDescription Package Type Package Marking Supplied As:ADJ LP3876ES-ADJ 3A TO263-5 LP3876ES-ADJ RailADJ LP3876ESX-ADJ 3A TO263-5 LP3876ES-ADJ Tape and ReelADJ LP3876ET-ADJ 3A TO220-5 LP3876ET-ADJ RailLP3876-ADJwww.national.com 2Block Diagram LP3876-ADJ20074429LP3876-ADJwww.national.com3Absolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.Storage Temperature Range −65˚C to +150˚CLead Temperature(Soldering, 5 sec.) 260˚CESD Rating (Note 3) 2 kVPower Dissipation (Note 2) Internally LimitedInput Supply Voltage (Survival) −0.3V to +7.5VShutdown Input Voltage(Survival) −0.3V to 7.5VOutput Voltage (Survival), (Note6), (Note 7) −0.3V to +6.0VIOUT(Survival) Short Circuit ProtectedOperating RatingsInput Supply Voltage (Operating),(Note 10) 2.5V to 7.0VShutdown Input Voltage(Operating) −0.3V to 7.0VMaximum Operating Current (DC) 3AOperating Junction Temp. Range −40˚C to +125˚CElectrical CharacteristicsLP3876-ADJLimits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range.Unless otherwise specified: VIN=VO(NOM)+ 1.5V, IL= 10 mA, COUT= 10µF, VSD= 2V.Symbol Parameter Conditions Typ(Note 4)LP3876-ADJ (Note 5) UnitsMin MaxVADJAdjust Pin VoltageVOUT+1.5V ≤ VIN≤ 7V10 mA ≤ IL≤ 3A1.2161.1981.1801.2341.253VIADJAdjust Pin Input Current VOUT+1.5V ≤ VIN≤ 7V10 mA ≤ IL≤ 3A10 100 nA∆VOLOutput Voltage LineRegulation (Note 8)VOUT+1.5V ≤ VIN≤ 7.0V 0.020.06%∆VO/ ∆IOUTOutput Voltage LoadRegulation(Note 8)10 mA ≤ IL≤ 3A 0.080.14%VIN-VOUTDropout Voltage(Note 9)IL= 300 mA 80 105125mVIL= 3A 800 10001200IGNDGround Pin Current InNormal Operation ModeIL= 300 mA 5 910mAIL=3A 6 1415IGNDGround Pin Current InShutdown ModeVSD≤ 0.3V 1 10 µA-40˚C ≤TJ≤ 85˚C 50IO(PK)Peak Output Current VO≥ VO(NOM)- 4% 4.5 ASHORT CIRCUIT PROTECTIONISCShort Circuit Current 6 ALP3876-ADJwww.national.com 4Electrical CharacteristicsLP3876-ADJ(Continued)Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range.Unless otherwise specified: VIN=VO(NOM)+ 1.5V, IL= 10 mA, COUT= 10µF, VSD= 2V.Symbol Parameter Conditions Typ(Note 4)LP3876-ADJ (Note 5) UnitsMin MaxSHUTDOWN INPUTVSDTShutdown ThresholdOutput = High VIN2VOutput = Low 0 0.3TdOFFTurn-off delay IL=3A 20 µsTdONTurn-on delay IL=3A 25 µsISDSD Input Current VSD=VIN1nAAC PARAMETERSPSRR Ripple RejectionVIN=VOUT+1VCOUT= 10uFVOUT= 3.3V, f = 120Hz73dBVIN=VOUT+ 0.5VCOUT= 10uFVOUT= 3.3V, f = 120Hz57ρn(l/fOutput Noise Density f = 120Hz 0.8 µVenOutput Noise VoltageBW = 10Hz – 100kHzVOUT= 2.5V150µV (rms)BW = 300Hz – 300kHzVOUT= 2.5V100Note 1: Absolute maximum ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device isintended to be functional, but does not guarantee specific performance limits. For guaranteed specifications and test conditions, see Electrical Characteristics. Theguaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listedtest conditions.Note 2: At elevated temperatures, devices must be derated based on package thermal resistance. The devices in TO220 package must be derated at θjA= 50˚C/W(with 0.5in2, 1oz. copper area), junction-to-ambient (with no heat
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