LM3940IT-3.3 National Semiconductor, LM3940IT-3.3 Datasheet

IC, LDO VOLT REG, 3.3V, 1A, TO-220

LM3940IT-3.3

Manufacturer Part Number
LM3940IT-3.3
Description
IC, LDO VOLT REG, 3.3V, 1A, TO-220
Manufacturer
National Semiconductor
Datasheet

Specifications of LM3940IT-3.3

Primary Input Voltage
5V
Output Voltage Fixed
3.3V
Dropout Voltage Vdo
110mV
No. Of Pins
3
Output Current
1A
Operating Temperature Range
-40°C To +125°C
Termination Type
Through Hole
Dc
N/A
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

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© 2007 National Semiconductor Corporation
LM3940
1A Low Dropout Regulator for 5V to 3.3V Conversion
General 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 ap-
plications 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.
Typical Application
*Required if regulator is located more than 1 from the power supply filter capacitor or if battery power is used.
**See Application Hints.
Connection Diagram/Ordering Information
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
(Front View)
(Front View)
1208003
12080
1208002
Features
Applications
Output voltage specified over temperature
Excellent load regulation
Guaranteed 1A output current
Requires only one external component
Built-in protection against excess temperature
Short circuit protected
Laptop/Desktop Computers
Logic Systems
Order Part Number LM3940IMP-3.3
NSC Drawing Number MP04A
Package Marked L52B
3-Lead SOT-223
(Front View)
1208001
1208010
www.national.com
July 2007

Related parts for LM3940IT-3.3

LM3940IT-3.3 Summary of contents

Page 1

... Application Hints. Connection Diagram/Ordering Information 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 © ...

Page 2

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 www.national.com 1208027 Pin 2 and pin 7 are fused to ...

Page 3

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Storage Temperature Range Lead Temperature (Soldering, 5 seconds) Power Dissipation (Note 2) Electrical Characteristics Limits in standard typeface are for T = 25°C, and limits in boldface type apply over the full operating temperature range. Unless ...

Page 4

Typical Performance Characteristics Dropout Voltage Output Voltage vs. Temperature Quiescent Current vs. V www.national.com Dropout Voltage vs. Temperature 1208013 Quiescent Current vs. Temperature 1208015 Quiescent Current vs. Load IN 1208017 4 1208014 1208016 1208018 ...

Page 5

Line Transient Response 1208019 Ripple Rejection 1208021 Output Impedance 1208023 Load Transient Response Low Voltage Behavior Peak Output Current 5 1208020 1208022 1208024 www.national.com ...

Page 6

Application Hints EXTERNAL CAPACITORS The output capacitor is critical to maintaining regulator stabil- ity, and must meet the required conditions for both ESR (Equivalent Series Resistance) and minimum amount of ca- pacitance. MINIMUM CAPACITANCE: The minimum output capacitance required to ...

Page 7

If a manufactured heatsink selected, the value of heatsink-to-ambient thermal resistance, θ calculated: θ = θ − θ − θ (H−A) (JA) (C−H) (J−C) Where: θ is defined as the thermal resistance from the (J−C) junction to ...

Page 8

... Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 3-Lead SOT-223 Package Order Part Number LM3940IMP-3.3 NSC Package Number MP04A 3-Lead TO-220 Package Order Part Number LM3940IT-3.3 NSC Package Number TO3B 8 ...

Page 9

TO-263 Package Order Part Number LM3940IS-3.3 NSC Package Number TS3B 16-Lead Ceramic Dual-in-Line Package Order Part Number LM3940J-3.3-QML 5962-9688401QEA NSC Drawing Number J16A 9 www.national.com ...

Page 10

Ceramic Surface-Mount Package Order Part Number LM3940WG-3.3-QML 5962-9688401QXA NSC Package Number WG16A 8-Lead LLP Order Part Number LM3940LD-3.3 NSC Package Number LDC08A 10 ...

Page 11

Notes 11 www.national.com ...

Page 12

... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...

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