Document
LM2940/LM2940C 1A Low Dropout Regulator
March 2000
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 reduces the 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 input-output 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 all regulated 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 regulator features 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
DS008822-3
to the regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.
*Required if regulator 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
Ordering Information
Temperature Range 0˚C ≤ TJ ≤ 125˚C −40˚C ≤ TJ ≤ 125˚C −40˚C ≤ TJ ≤ 85˚C Output Voltage 5.0 LM2940CT-5.0 LM2940CS-5.0 LM2940T-5.0 LM2940S-5.0 LM2940IMP-5.0 LM2940T-8.0 LM2940S-8.0 LM2940IMP-8.0 8.0 9.0 LM2940CT-9.0 LM2940CS-9.0 LM2940T-9.0 LM2940S-9.0 LM2940IMP-9.0 LM2940T-10 LM2940S-10 LM2940IMP-10 10 12 LM2940CT-12 LM2940CS-12 LM2940T-12 LM2940S-12 LM2940IMP-12 LM2940IMP-15 15 LM2940CT-15 LM2940CS-15 Package TO-220 TO-263 TO-220 TO-263 SOT-223
LM2940IMPX-5.0 LM2940IMPX-8.0 LM2940IMPX-9.0 LM2940IMPX-10 LM2940IMPX-12 LM2940IMPX-15 SOT-223 in Tape and Reel SOT-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.
Temperature Range −55˚C ≤ TJ ≤ 125˚C 5.0 LM2940J-5.0/883 5962-8958701EA LM2940WG5.0/883 5962-8958701XA 8.0
Output Voltage 12 LM2940J-12/883 5962-9088401QEA 15 LM2940J-15/883 5962-9088501QEA LM2940J-8.0/883 5962-9088301QEA
Package J16A WG16A
For information on military temperature range products, please go to the Mil/Aero Web Site at http://www.national.com/appinfo/milaero/index.html.
© 2000 National Semiconductor Corporation
DS008822
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LM2940/LM2940C
Connection Diagrams
(TO-220) Plastic Package 3-Lead SOT-223
DS008822-2
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)
DS008822-42
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 MP04A
16-Lead Ceramic Surface-Mount Package (WG)
DS008822-43
Top View Order Number LM2940J-5.0/883 (5962-8958701EA), LM2940J-8.0/883 (5962-9088301QEA), LM2940J-12/883 (5962-9088401QEA), LM2940J-15/883 (5962-9088501QEA) See NS Package Number J16A
DS008822-44
Top View Order Number LM2940WG5.0/883 (5962-8958701XA) See NS Package Number WG16A
(TO-263) Surface-Mount Package
DS008822-11
Top View
DS008822-12
Side View Order Number LM2940CS-5.0, LM2940CS-9.0, LM2940CS-12, LM2940CS-15, LM2940S-5.0, LM2940S-8.0, LM2940S-9.0, LM2940S-10 or LM2940S-12 See NS Package Number TS3B
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LM2940/LM2940C
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. LM2940S, T, MP ≤ 100 ms 60V LM2940CS, T ≤ 1 ms 45V Internal Power Dissipation (Note 2) Internally Limited Maximum Junction Temperature 150˚C Storage Temperature Range −65˚C ≤ TJ ≤ +150˚C Lead Temperature, Time for Wave Soldering TO-220 (T) Package 260˚C, 10s
TO-263 (S) Package SOT-223 (MP) Package ESD Susceptibility (Note 3)
260˚C, 4s 260˚C, 4s 2 kV
Operating Conditions (Note 1)
Input Voltage Temperature Range LM2940T, LM2940S LM2940CT, LM2940CS LM2940IMP LM2940J, LM2940WG 26V −40˚C ≤ TJ ≤ 125˚C 0˚C ≤ TJ ≤ 125˚C −40˚C ≤ TJ ≤ 85˚C −55˚C ≤ T.