LM3940_15 Datasheet, PDF (1/24 Pages) Texas Instruments – LM3940 1-A Low-Dropout Regulator for 5-V to 3.3-V Conversion

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LM3940
SNVS114G – MAY 1999 – REVISED FEBRUARY 2015
LM3940 1-A Low-Dropout Regulator for 5-V to 3.3-V Conversion
1 Features
•1 Input Voltage Range: 4.5 V to 5.5 V
• Output Voltage Specified over Temperature
• Excellent Load Regulation
• Specified 1-A Output Current
• Requires only One External Component
• Built-in Protection against Excess Temperature
• Short-Circuit Protected
2 Applications
• Laptop and Desktop Computers
• Logic Systems
3 Description
The LM3940 is a 1-A low-dropout regulator designed
to provide 3.3 V from a 5-V supply.
The LM3940 is ideally suited for systems which
contain both 5-V and 3.3-V logic, with prime power
provided from a 5-V bus.
Because the LM3940 is a true low dropout regulator,
it can hold its 3.3-V output in regulation with input
voltages as low as 4.5 V.
The TO-220 package of the LM3940 means that in
most applications the full 1 A of load current can be
delivered without using an additional heatsink.
The surface mount DDPAK/TO-263 package uses
minimum board space, and gives excellent power
dissipation capability when soldered to a copper
plane on the PC board.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
SOT-223 (4)
6.50 mm x 3.50 mm
LM3940
DDPAK/TO-263 (3) 10.18 mm x 8.41 mm
TO-220 (3)
14.986 mm x 10.16 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
*Required if regulator is located more than 1 inch from the power supply filter capacitor or if battery power is used.
**See Application and Implementation.
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.