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LM2940/LM2940C 1A Low Dropout Regulator

January 2003

LM2940/LM2940C 1A Low Dropout Regulator
General Description
The LM2940/LM2940C positive voltage regulator features the ability to source 1A of output current with a dropout voltage of typically 0.5V and a maximum of 1V over the entire temperature range. Furthermore, a quiescent current reduction circuit has been included which reducesthe ground current when the differential between the input voltage and the output voltage exceeds approximately 3V. The quiescent current with 1A of output current and an inputoutput differential of 5V is therefore only 30 mA. Higher quiescent currents only exist when the regulator is in the dropout mode (VIN − VOUT ≤ 3V). Designed also for vehicular applications, the LM2940/ LM2940C and allregulated circuitry are protected from reverse battery installations or 2-battery jumps. During line transients, such as load dump when the input voltage can momentarily exceed the specified maximum operating voltage, the regulator will automatically shut down to protect both the internal circuits and the load. The LM2940/ LM2940C cannot be harmed by temporary mirror-image insertion. Familiar regulatorfeatures such as short circuit and thermal overload protection are also provided.

Features
n n n n n n n Dropout voltage typically 0.5V @IO = 1A Output current in excess of 1A Output voltage trimmed before assembly Reverse battery protection Internal short circuit current limit Mirror image insertion protection P+ Product Enhancement tested

Typical Application

00882203

*Required ifregulator is located far from power supply filter. **COUT must be at least 22 µF to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to the regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.

Ordering Information
Temperature Range 0˚C ≤ TJ ≤125˚C −40˚C ≤ TJ ≤ 125˚C Output Voltage 5.0 LM2940CT-5.0 LM2940CS-5.0 LM2940LD-5.0 LM2940LD-8.0 8.0 9.0 LM2940CT-9.0 LM2940CS-9.0 LM2940LD-9.0 LM2940LD-10 10 12 LM2940CT-12 LM2940CS-12 LM2940LD-12 15 LM2940CT-15 LM2940CS-15 LM2940LD-15 Package TO-220 TO-263 LLP 1k Units Tape and Reel LLP 4.5k Units Tape and Reel TO-220 TO-263 LM2940IMP-15 SOT-223 SOT-223 in Tape and Reel

LM2940LDX-5.0LM2940LDX-8.0 LM2940LDX-9.0

LM2940LDX-10 LM2940LDX-12

LM2940LDX-15

−40˚C ≤ TJ ≤ 125˚C −40˚C ≤ TJ ≤ 85˚C

LM2940T-5.0 LM2940S-5.0 LM2940IMP-5.0

LM2940T-8.0 LM2940S-8.0 LM2940IMP-8.0

LM2940T-9.0 LM2940S-9.0 LM2940IMP-9.0

LM2940T-10 LM2940S-10 LM2940IMP-10

LM2940T-12 LM2940S-12 LM2940IMP-12

LM2940IMPX-5.0 LM2940IMPX-8.0 LM2940IMPX-9.0 LM2940IMPX-10 LM2940IMPX-12 LM2940IMPX-15SOT-223 Package Marking

L53B

L54B

L0EB

L55B

L56B

L70B

The physical size of the SOT-223 is too small to contain the full device part number. The package markings indicated are what will appear on the actual device.

© 2003 National Semiconductor Corporation

DS008822

www.national.com

LM2940/LM2940C

Ordering Information
Temperature Range −55˚C ≤ TJ ≤ 125˚C 5.0(Continued) Output Voltage 8.0 LM2940J-8.0/883 5962-9088301QEA 12 LM2940J-12/883 5962-9088401QEA 15 LM2940J-15/883 5962-9088501QEA J16A WG16A Package

LM2940J-5.0/883 5962-8958701EA LM2940WG5.0/883 5962-8958701XA

For information on military temperature range products, please go to the Mil/Aero Web Site at http://www.national.com/appinfo/milaero/index.html.

Connection Diagrams
(TO-220)Plastic Package 3-Lead SOT-223

00882202

Front View Order Number LM2940CT-5.0, LM2940CT-9.0, LM2940CT-12, LM2940CT-15, LM2940T-5.0, LM2940T-8.0, LM2940T-9.0, LM2940T-10 or LM2940T-12 See NS Package Number TO3B 16-Lead Dual-in-Line Package (J)

00882242

Front View Order Part Number LM2940IMP-5.0, LM2940IMP-8.0, LM2940IMP-9.0, LM2940IMP-10, LM2940IMP-12 or LM2940IMP-15 See NS Package Number...