LM2940-N_15 Datasheet, PDF (1/37 Pages) Texas Instruments – LM2940x 1-A Low Dropout Regulator

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LM2940-N, LM2940C
SNVS769J – MARCH 2000 – REVISED DECEMBER 2014
LM2940x 1-A Low Dropout Regulator
1 Features
•1 Input Voltage Range = 6 V to 26 V
• Dropout Voltage Typically 0.5 V at I_OUT = 1 A
• Output Current in Excess of 1 A
• Output Voltage Trimmed Before Assembly
• Reverse Battery Protection
• Internal Short Circuit Current Limit
• Mirror Image Insertion Protection
• P⁺ Product Enhancement Tested
2 Applications
• Post Regulator for Switching Supplies
• Logic Power Supplies
• Industrial Instrumentation
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3 Description
The LM2940-N and LM2940C positive voltage
regulators feature the ability to source 1 A of output
current with a dropout voltage of typically 0.5 V and a
maximum of 1 V 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 3 V. The
quiescent current with 1 A of output current and an
input-output differential of 5 V is therefore only 30
mA. Higher quiescent currents only exist when the
regulator is in the dropout mode (V_IN − V_OUT ≤ 3 V).
Designed also for vehicular applications, the LM2940-
N and 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-N and
LM2940C cannot be harmed by temporary mirror-
image insertion. Familiar regulator features such as
short circuit and thermal overload protection are also
provided.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
SOT-223 (4) 6.50 mm x 3.50 mm
LM2940-N
WSON (8)
TO-263 (3)
4.00 mm x 4.00 mm
10.18 mm x 8.41 mm
TO-220 (3)
14.986 mm x 10.16 mm
LM2940C
TO-263 (3)
TO-220 (3)
10.18 mm x 8.41 mm
14.986 mm x 10.16 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
V_IN
Unregulated Input
C1*
0.47 µF
IN
LM2940 ^OUT
I_Q
V_OUT
Regulated Output
+ _COUT**
22 µF
*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.
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.