Datasheet

LM2940-N, LM2940C
www.ti.com SNVS769H –MAY 2004–REVISED MARCH 2007
LM2940/LM2940C 1A Low Dropout Regulator
Check for Samples: LM2940-N, LM2940C
1
FEATURES
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• Dropout voltage typically 0.5V @I
O
= 1A
• Internal short circuit current limit
• Output current in excess of 1A • Mirror image insertion protection
• Output voltage trimmed before assembly • P
+
Product Enhancement tested
• Reverse battery protection
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 (V
IN
− V
OUT
≤ 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.
Typical Application
*Required if regulator is located far from power supply filter.
**C
OUT
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.
Connection Diagrams
Figure 1. Front View - TO-220 (T) Plastic Package
Figure 2. Front View - SOT-223 (MP) 3-Lead
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PRODUCTION DATA information is current as of publication date.
Copyright © 2004–2007, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.