LM3940IS-3.3 National Semiconductor, LM3940IS-3.3 Datasheet

V REG LDO +3.3V, 3940, SOT-263-3

LM3940IS-3.3

Manufacturer Part Number
LM3940IS-3.3
Description
V REG LDO +3.3V, 3940, SOT-263-3
Manufacturer
National Semiconductor
Datasheet

Specifications of LM3940IS-3.3

Primary Input Voltage
5V
Output Voltage
3.3V
Dropout Voltage Vdo
110mV
No. Of Pins
3
Output Current
1A
Voltage Regulator Case Style
SOT-263
Operating Temperature Range
-40°C To +125°C
Svhc
No
Output Voltage Fixed
3.3V
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

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© 2003 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
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.
Typical Application
*
**
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
(Front View)
(Front View)
01208003
DS012080
01208002
Features
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
Applications
n Laptop/Desktop Computers
n Logic Systems
Order Part Number LM3940IMP-3.3
NSC Drawing Number MP04A
Package Marked L52B
3-Lead SOT-223
(Front View)
01208001
01208010
January 2003
www.national.com

LM3940IS-3.3 Summary of contents

Page 1

... 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 © 2003 National Semiconductor Corporation Features n Output voltage specified over temperature n Excellent load regulation n Guaranteed 1A output current ...

Page 2

Connection Diagram/Ordering Information (Continued) 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 www.national.com Pin 2 and pin 7 ...

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 Operating Junction Temperature Range −40˚C to +125˚C Electrical Characteristics Limits in standard typeface are for T less otherwise specified: V ...

Page 4

Typical Performance Characteristics Dropout Voltage Output Voltage vs. Temperature Quiescent Current vs. V www.national.com Dropout Voltage vs. Temperature 01208013 Quiescent Current vs. Temperature 01208015 Quiescent Current vs. Load IN 01208017 4 01208014 01208016 01208018 ...

Page 5

Typical Performance Characteristics Line Transient Response Ripple Rejection Output Impedance (Continued) Load Transient Response 01208019 01208021 01208023 5 01208020 Low Voltage Behavior 01208022 Peak Output Current 01208024 www.national.com ...

Page 6

Application Hints EXTERNAL CAPACITORS The output capacitor is critical to maintaining regulator sta- bility, 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

Application Hints (Continued 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 ...

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

... Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 3-Lead 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

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted (Continued) 16-Lead 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

... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...

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