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 volt-

age 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 (V

≤ 3V).

Designed also for vehicular applications, the LM2940/

LM2940C and all regulated circuitry are protected from re-

verse battery installations or 2-battery jumps. During line

transients, such as load dump when the input voltage can

momentarily exceed the specified maximum operating volt-

age, 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 in-

sertion. Familiar regulator features such as short circuit and

thermal overload protection are also provided.

Features

n

n

Output current in excess of 1A

n

Output voltage trimmed before assembly

n

Reverse battery protection

n

Internal short circuit current limit

n

Mirror image insertion protection

n

P

Typical Application

00882203

*Required if regulator is located far from power supply filter.

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

Output Voltage

Package

5.0

8.0

9.0

10

12

15

0˚C

LM2940CT-9.0

LM2940CT-12

LM2940CT-15

TO-220

LM2940CS-5.0

LM2940CS-9.0

LM2940CS-12

LM2940CS-15

TO-263

−40˚C

125˚C

LM2940LD-5.0

LM2940LD-8.0

LM2940LD-9.0

LM2940LD-10

LM2940LD-12

LM2940LD-15

LLP 1k

Units

Tape and

Reel

LM2940LDX-5.0

LM2940LDX-8.0

LM2940LDX-9.0

LM2940LDX-10

LM2940LDX-12

LM2940LDX-15

LLP 4.5k

Units

Tape and

Reel

−40˚C

125˚C

LM2940T-5.0

LM2940T-8.0

LM2940T-9.0

LM2940T-10

LM2940T-12

TO-220

LM2940S-5.0

LM2940S-8.0

LM2940S-9.0

LM2940S-10

LM2940S-12

TO-263

−40˚C

85˚C

LM2940IMP-5.0

LM2940IMP-8.0

LM2940IMP-9.0

LM2940IMP-10

LM2940IMP-12

LM2940IMP-15

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.

January 2003

© 2003 National Semiconductor Corporation

DS008822

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