LM3940IT33NOPB National Semiconductor, LM3940IT33NOPB Datasheet
Manufacturer Part Number
Specifications of LM3940IT33NOPB
© 2003 National Semiconductor Corporation
1A Low Dropout Regulator for 5V to 3.3V Conversion
The LM3940 is a 1A low dropout regulator designed to
provide 3.3V from a 5V supply.
The LM3940 is ideally suited for systems which contain both
5V and 3.3V logic, with prime power provided from a 5V bus.
Because the LM3940 is a true low dropout regulator, it can
hold its 3.3V output in regulation with input voltages as low
The T0-220 package of the LM3940 means that in most
applications the full 1A of load current can be delivered
without using an additional heatsink.
The surface mount TO-263 package uses minimum board
space, and gives excellent power dissipation capability when
soldered to a copper plane on the PC board.
Connection Diagram/Ordering Information
Required if regulator is located more than 1" from the power supply filter capacitor or if battery power is used.
See Application Hints.
Order Part Number LM3940IT-3.3
Order Part Number LM3940IS-3.3
NSC Drawing Number TO3B
NSC Drawing Number TS3B
3-Lead TO-220 Package
3-Lead TO-263 Package
n Output voltage specified over temperature
n Excellent load regulation
n Guaranteed 1A output current
n Requires only one external component
n Built-in protection against excess temperature
n Short circuit protected
n Laptop/Desktop Computers
n Logic Systems
Order Part Number LM3940IMP-3.3
NSC Drawing Number MP04A
Package Marked L52B