LM3940 Datasheet | National Semiconductor

Description 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 as 4.5V. 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. Features n n n n n n Output voltage specified over temperature Excellent load regulation Guaranteed 1A output current Requires only one external ponent Built-in protection against excess temperature Short circuit protected Applications n Laptop/Desktop puters n Logic Systems Typical Application DS012080-1 - Required if regulator is located more than 1" from the power supply filter capacitor or if battery power is used. - - See Application Hints. © 1999 National Semiconductor Corporation DS012080 .national. .. Connection Diagram/Ordering Information DS012080-2 DS012080-3 3-Lead TO-220 Package (Front View) Order Part Number LM3940IT-3.3 NSC Drawing Number TO3B 3-Lead TO-263 Package (Front View) Order Part Number LM3940IS-3.3 NSC Drawing Number TS3B DS012080-10 3-Lead SOT-223 (Front View) Order Part Number LM3940IMP-3.3 Package Marked L52B NSC Drawing Number MA04A DS012080-27 DS012080-28 16-Lead Ceramic Dual-in-Line Package (Top View) Order Part Number LM3940J-3.3-QML 5962-9688401QEA NSC Drawing Number J16A 16-Lead Ceramic Surface-Mount Package (Top View) Order Part Number LM3940WG-3.3-QML 5962-9688401QXA NSC Drawing Number WG16A .national. .. Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for...