LM2937-2.5, LM2937-3.3General DescriptionFeaturesConnection Diagrams and Ordering InformationTO-263 Surface-Mount PackageAbsolute Maximum RatingsOperating ConditionsElectrical CharacteristicsTypical Performance CharacteristicsTypical ApplicationApplication HintsEXTERNAL CAPACITORSFIGURE 1. ESR Limits HEATSINKINGFIGURE 2. Power Dissipation Diagram HEATSINKING TO-220 PACKAGE PARTSHEATSINKING TO-263 AND SOT-223 PACKAGE PARTSFIGURE 3. (J-A) vs Copper (1 ounce) Area for the TO-263 Package FIGURE 4. Maximum Power Dissipation vs TAMB for the TO-263 Package FIGURE 5. (J-A) vs Copper (2 ounce) Area for the SOT-223 Package FIGURE 6. Maximum Power Dissipation vs TAMB for the SOT-223 Package SOT-223 SOLDERING RECOMMENDATIONSPhysical DimensionsLM2937-2.5, LM2937-3.3400mA and 500mA Voltage RegulatorsGeneral DescriptionThe LM2937-2.5 and LM2937-3.3 are positive voltage regu-lators capable of supplying up to 500 mA of load current.Both regulators are ideal for converting a common 5V logicsupply, or higher input supply voltage, to the lower 2.5V and3.3V supplies to power VLSI ASIC’s and microcontrollers.Special circuitry has been incorporated to minimize the qui-escent current to typically only 10 mA with a full 500 mA loadcurrent when the input to output voltage differential is greaterthan 5V.The LM2937 requires an output bypass capacitor for stabil-ity. As with most regulators utilizing a PNP pass transistor,the ESR of this capacitor remains a critical design param-eter, but the LM2937-2.5 and LM2937-3.3 include specialcompensation circuitry that relaxes ESR requirements. TheLM2937 is stable for all ESR ratings less than 5Ω. Thisallows the use of low ESR chip capacitors.The regulators are also suited for automotive applications,with built in protection from reverse battery connections,two-battery jumps and up to +60V/−50V load dump tran-sients. Familiar regulator features such as short circuit andthermal shutdown protection are also built in.Featuresn Fully specified for operation over −40˚C to +125˚Cn Output current in excess of 500 mA (400mA forSOT-223 package)n Output trimmed for 5% tolerance under all operatingconditionsn Wide output capacitor ESR range, 0.01Ω up to 5Ωn Internal short circuit and thermal overload protectionn Reverse battery protectionn 60V input transient protectionn Mirror image insertion protectionConnection Diagrams and Ordering InformationTO-220 Plastic Package SOT-223 Plastic Package10011324Front ViewOrder Number LM2937ET-2.5, LM2937ET-3.3,See NS Package Number T03B10011325Front ViewOrder Number LM2937IMP-2.5, LM2937IMP-3.3,See NS Package Number MA04ATO-263 Surface-Mount Package10011326Top View10011327Side ViewOrder Number LM2937ES-2.5, LM2937ES-3.3,See NS Package Number TS3BAugust 2005LM2937-2.5, LM2937-3.3 400mA and 500mA Voltage Regulators© 2005 National Semiconductor Corporation DS100113 www.national.comConnection Diagrams and Ordering Information (Continued)TemperatureRangeOutput Voltage NSC Package2.5 3.3 PackageDrawing−40˚C ≤ TA≤ 125˚C LM2937ES-2.5 LM2937ES-3.3 TS3B TO-263LM2937ET-2.5 LM2937ET-3.3 T03B TO-220−40˚C ≤ TA≤ 85˚C LM2937IMP-2.5 LM2937IMP-3.3 MA04A SOT-223SOT-223 PackageMarkingsL68B L69BThe small physical size of the SOT-223 package does not allow sufficient space to provide the complete device part number. The actual devices will be labeled withthe package markings shown.LM2937-2.5, LM2937-3.3www.national.com 2Absolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.Input VoltageContinuous 26VTransient (t ≤ 100 ms) 60VInternal Power Dissipation (Note 2) Internally LimitedMaximum Junction Temperature 150˚CStorage Temperature Range −65˚C to +150˚CLead Temperature SolderingTO-220 (10 seconds) 260˚CTO-263 (10 seconds) 230˚CSOT-223 (Vapor Phase, 60 seconds) 215˚CSOT-223 (Infrared, 15 seconds) 220˚CESD Susceptibility (Note 3) 2 kVOperating Conditions(Note 1)Temperature Range (Note 2)LM2937ES, LM2937ET −40˚C ≤ TA≤125˚CLM2937IMP −40˚C ≤ TA≤ 85˚CInput Voltage Range 4.75V to 26VElectrical Characteristics(Note 4)VIN=VNOM+ 5V, IOUTmax= 500 mA for the TO-220 and TO-263 packages, IOUTmax=400mA for the SOT-223 package, COUT=10 µF unless otherwise indicated. Boldface limits apply over the entire operating temperature range, of the indicated de-vice, all other specifications are for TA=TJ= 25˚C.Output Voltage (VOUT) 2.5V 3.3V UnitsParameter Conditions Typ Limit Typ LimitOutput Voltage 5 mA ≤ IOUT≤ IOUTmax2.42 3.20 V (Min)2.5 2.38 3.3 3.14 V(Min)2.56 3.40 V(Max)2.62 3.46 V(Max)Line Regulation(Note 5) 4.75V ≤ VIN≤ 26V, 7.5 25 9.9 33 mV(Max)IOUT=5mALoad Regulation 5 mA ≤ IOUT≤ IOUTmax2.5 25 3.3 33 mV(Max)Quiescent Current 7V ≤ VIN≤ 26V, 2 10 2 10 mA(Max)IOUT=5mAVIN=(VOUT+ 5V), 10 20 10 20 mA(Max)IOUT=IOUTmaxVIN= 5V, IOUT=IOUTmax66 100125 66 100125 mA(Max)Output Noise 10 Hz–100 kHz, 75 99 µVrmsVoltage IOUT=5mALong Term Stability 1000 Hrs. 10 13.2 mVShort-Circuit Current 1.0 0.6 1.0 0.6 A(Min)Peak Line Transient tf<100 ms, RL= 100Ω 75 60 75 60 V(Min)VoltageMaximum Operational 26 26 V(Min)Input VoltageReverse DC VOUT≥ −0.6V, RL= 100Ω −30 −15 −30 −15 V(Min)Input VoltageReverse Transient tr<1 ms, RL= 100Ω −75 −50 −75 −50 V(Min)Input VoltageNote 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the deviceoutside of its rated Operating Conditions.Note 2: The maximum allowable power dissipation at any ambient temperature is PMAX= (125 − TA)/θJA, where 125 is the maximum junction temperature foroperation, TAis the ambient temperature, and θJAis the junction-to-ambient thermal resistance. If this dissipation is exceeded, the die temperature will rise above125˚C and the electrical specifications do not apply. If the die temperature rises above 150˚C, the regulator will go into thermal shutdown. The junction-to-ambientthermal resistance θJAis 65˚C/W, for the TO-220 package, 73˚C/W for the TO-263 package, and 174˚C/W for the SOT-223 package. When used with a heatsink,θJAis the sum of the device junction-to-case thermal resistance θJCof 3˚C/W and the heatsink case-to-ambient thermal resistance. If the TO-263 or SOT-223packages are used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the