LM2941QML
LM2941QML 1A Low Dropout Adjustable Regulator
Literature Number: SNVS390A
LM2941QML
October 12, 2011
1A Low Dropout Adjustable Regulator
General Description
The LM2941 positive voltage regulator features the ability to
source 1A of output current with a typical dropout voltage of
0.5V and a maximum of 1V over the entire temperature range.
Furthermore, a quiescent current reduction circuit has been
included which reduces the ground pin current when the dif-
ferential between the input voltage and the output voltage
exceeds approximately 3V. The quiescent current with 1A of
output current and an input-output differential of 5V is there-
fore only 30mA. Higher quiescent currents only exist when the
regulator is in the dropout mode (VI − VO ≤ 3V).
Originally designed for vehicular applications, the LM2941
and all regulated circuitry are protected from reverse battery
installations or two-battery jumps. During line transients, such
as load dump when the input voltage can momentarily exceed
the specified maximum operating voltage, the regulator will
automatically shut down to protect both the internal circuits
and the load. Familiar regulator features such as short circuit
and thermal overload protection are also provided.
Features
■Available with radiation guarantee
—ELDRS Free 100 krad(Si)
■Output voltage adjustable from 5V to 20V
■Dropout voltage typically 0.5V @ IO = 1A
■Output current in excess of 1A
■Trimmed reference voltage
■Reverse battery protection
■Internal short circuit current limit
■Mirror image insertion protection
■TTL, CMOS compatible ON/OFF switch
Ordering Information
NS Part Number SMD Part Number NS Package Number Package Description
LM2941WG/883 5962-9166701QYA WG16A 16LD Ceramic SOIC
LM2941WG-QMLV 5962-9166701VYA WG16A 16LD Ceramic SOIC
LM2941WGRLQMLV
ELDRS FREE (Note 10)
5962R9166702VYA
100 krad(Si) WG16A 16LD Ceramic SOIC
LM2941GW/883 5962-9166703QYA WG16A 16LD Ceramic SOIC
LM2941GW-QMLV 5962-9166703VYA WG16A 16LD Ceramic SOIC
LM2941GWRLQMLV
ELDRS FREE (Note 10)
5962R9166704VYA
100 krad(Si) WG16A 16LD Ceramic SOIC
LM2941 MDE
ELDRS FREE (Note 10)
5962R9166702V9A
100 krad(Si) (Note 1) Bare Die
Note 1: FOR ADDITIONAL DIE INFORMATION, PLEASE VISIT THE HI REL WEB SITE AT: www.national.com/analog/space/level_die
Connection Diagrams
16-Lead Ceramic Surface Mount Package
20158532
Top View
See NS Package Number WG16A
© 2011 National Semiconductor Corporation 201585 www.national.com
LM2941QML 1A Low Dropout Adjustable Regulator
Equivalent Schematic Diagram
20158501
www.national.com 2
LM2941QML
Absolute Maximum Ratings (Note 2)
Input Voltage (Survival Voltage, ≤ 100ms) 60V
Internal Power Dissipation (Note 3) Internally Limited
Maximum Junction Temperature 150°C
Storage Temperature Range −65°C ≤ TJ ≤ +150°C
Lead Temperature (Soldering, 10 seconds) 300°C
Thermal Resistance
θJA
Ceramic SOIC (Still Air) 'WG' 122°C/W
Ceramic SOIC (500LF/Min Air Flow) 'WG' 77°C/W
Ceramic SOIC (Still Air) 'GW' 136°C/W
Ceramic SOIC (500LF/Min Air Flow) 'GW' 87°C/W
θJC
Ceramic SOIC 'WG'(Note 4) 5°C/W
Ceramic SOIC 'GW' 13°C/W
Package Weight (Typ)
Ceramic SOIC 'WG' 360mg
Ceramic SOIC 'GW' 410mg
ESD susceptibility to be determined. (Note 5) 500V
Recommended Operating Conditions
Maximum Input Voltage 26V
Temperature Range −55°C ≤ TA ≤ 125°C
Quality Conformance Inspection
Mil-Std-883, Method 5005 - Group A
Subgroup Description Temp °C
1 Static tests at +25
2 Static tests at +125
3 Static tests at -55
4 Dynamic tests at +25
5 Dynamic tests at +125
6 Dynamic tests at -55
7 Functional tests at +25
8A Functional tests at +125
8B Functional tests at -55
9 Switching tests at +25
10 Switching tests at +125
11 Switching tests at -55
12 Settling time at +25
13 Settling time at +125
14 Settling time at -55
3 www.national.com
LM2941QML
LM2941 Electrical Characteristics
DC Parameters
The following conditions apply, unless otherwise specified.
DC: 5V ≤ VO ≤ 20V, VIN = VO+5V, CO = 22µF
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
VRef Reference Voltage 5mA ≤ IO ≤ 1A 1.237 1.313 V 1
1.211 1.339 V 2, 3
VRLine Line Regulation VO + 2V ≤ VIN ≤ 26V, IO = 5mA (Note 8) 10 mV/V 1, 2, 3
VRLoad Load Regulation
50mA ≤ IO ≤ 1A, VIN = 10V,
VOUT = 5V (Note 8)
10 mV/V 1, 2, 3
50mA ≤ IO ≤ 1A, VIN = 25V,
VOUT = 20V
10 mV/V 1, 2, 3
IQQuiescent Current
VO + 2V ≤ VIN ≤ 26V, IO = 5mA 15 mA 1
20 mA 2, 3
VIN = VO + 5V, IO = 1A 45 mA 1
60 mA 2, 3
VDO Dropout Voltage
IO = 1A 0.8 V 1
1.0 V 2, 3
IO = 100mA 200 mV 1
300 mV 2, 3
ISC Short Circuit Current VIN Max = 26V 1.6 3.5 A 1
1.3 3.7 A 2, 3
Maximum Operational Input
Voltage
(Note 7) 26 VDC 1, 2, 3
Reverse Polarity DC Input
Voltage
RO = 100Ω, VO ≥ -0.6V (Note 6) -15 V 1, 2, 3
VTH On ON/OFF Threshold Voltage ON IO ≤ 1A (Note 6) 0.8 V 1, 2, 3
VTh Off ON/OFF Threshold Voltage OFF IO ≤ 1A (Note 6) 2.00 V 1, 2, 3
ON/OFF Threshold Current VON/OFF = 2.0V, IO ≤ 1A 100 µA 1
300 µA 2, 3
AC Parameters
The following conditions apply, unless otherwise specified.
AC: 5V ≤ VO ≤ 20V, VIN = VO+5V, CO = 22µF
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
Maximum Line Transient VO Max 1V above nominal VO, RO
= 100Ω, t ≤ 100mS
60 V 4, 5, 6
Reverse Polarity Transient Input
Voltage
t ≤ 100mS, RO = 100Ω -50 V 4, 5, 6
RR Ripple Rejection ƒO = 1KHz, 1 VRMS, IL = 100mA (Note 9) 0.02 %/V 4
ƒO = 1KHz, 1 VRMS, IL = 100mA (Note 9) 0.04 %/V 5, 6
www.national.com 4
LM2941QML
DC Drift Parameters
The following conditions apply, unless otherwise specified.
DC: 5V ≤ VO ≤ 20V, VIN = VO+5V, CO = 22µF
Delta calculations performed on QMLV devices at group B , subgroup 5.
Symbol Parameter Conditions Notes Min Max Unit Sub-
groups
VRef Reference Voltage 5mA ≤ IO ≤ 1A -25 +25 mV 1
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJmax (maximum junction temperature), θJA (package
junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PDmax = (TJmax - TA)/
θJA or the number given in the Absolute Maximum Ratings, whichever is lower.
Note 4: The package material for these devices allows much improved heat transfer over our standard ceramic packages. In order to take full advantage of this
improved heat transfer, heat sinking must be provided between the package base (directly beneath the die), and either metal traces on, or thermal vias through,
the printed circuit board. Without this additional heat sinking, device power dissipation must be calculated using θJA, rather than θJC, thermal resistance. It must
not be assumed that the device leads will provide substantial heat transfer out of the package, since the thermal resistance of the lead frame material is very
poor, relative to the material of the package base. The stated θJC thermal resistance is for the package material only, and does not account for the additional
thermal resistance between the package base and the printed circuit board. The user must determine the value of the additional thermal resistance and must
combine this with the stated value for the package, to calculate the total allowed power dissipation for the device.
Note 5: Human body model, 1.5 kΩ in series with 100 pF.
Note 6: Functional test go-no-go only.
Note 7: Condition for VIN
Note 8: Limit = mV per volt of VO.
Note 9: %/V = % of VIN per Volt of VO.
Note 10: These parts are tested on a wafer by wafer basis at high and low dose rates according to MIL-STD-883 Test Method 1019 Conditions A and D with no
enhanced low dose rate sensitivity (ELDRS). Pre and post irradiation limits are identical to those listed under AC and DC electrical characteristics.
5 www.national.com
LM2941QML
Typical Performance Characteristics
Dropout Voltage
20158511
Dropout Voltage vs. Temperature
20158512
Output Voltage
20158513
Quiescent Current vs. Temperature
20158514
Quiescent Current
20158515
Quiescent Current
20158516
www.national.com 6
LM2941QML
Line Transient Response
20158517
Load Transient Response
20158518
Ripple Rejection
20158519
Output Impedance
20158520
Low Voltage Behavior
20158521
Low Voltage Behavior
20158522
7 www.national.com
LM2941QML
Output Capacitor ESR
20158523
Output at Voltage Extremes
20158524
Output at Voltage Extremes
20158525
Peak Output Current
20158526
www.national.com 8
LM2941QML
Typical Applications
5V to 20V Adjustable Regulator
20158503
Note: Using 1KΩ for R1 will ensure that the input bias current error of the adjust pin will be negligible. Do not bypass R1 or R2. This will lead to instabilities.
* Required if regulator is located far from power supply filter.
** CO must be at least 22μF to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to the
regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.
1A Switch
20158506
*** To assure shutdown, select Resistor R3 to guarantee at least 300μA of pull-up current when S1 is open. (Assume 2V at the ON/OFF pin.)
9 www.national.com
LM2941QML
Revision History Section
Released Revision Section Changes
08/25/09 A New Release, Corporate format 1 MDS data sheet converted into one Corp. data
sheet format. Added Radiation products to ordering
table. MNLM2941-X Rev 4A1 will be archived.
12–Oct-2011 B Ordering Information, Absolute Max Ratings Ordering Information — Added LM2941GW/883,
LM2941GW-QMLV and LM2941GWRLQMLV.
Absolute Max — Added Theta JA and Theta JC
along with Package weight of 'GW' devices.
RatingsLM2941QML Rev A will be archived.
www.national.com 10
LM2941QML
Physical Dimensions inches (millimeters) unless otherwise noted
16LD Ceramic SOIC
NS Package Number WG16A
11 www.national.com
LM2941QML
Notes
LM2941QML 1A Low Dropout Adjustable Regulator
For more National Semiconductor product information and proven design tools, visit the following Web sites at:
www.national.com
Products Design Support
Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench
Audio www.national.com/audio App Notes www.national.com/appnotes
Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns
Data Converters www.national.com/adc Samples www.national.com/samples
Interface www.national.com/interface Eval Boards www.national.com/evalboards
LVDS www.national.com/lvds Packaging www.national.com/packaging
Power Management www.national.com/power Green Compliance www.national.com/quality/green
Switching Regulators www.national.com/switchers Distributors www.national.com/contacts
LDOs www.national.com/ldo Quality and Reliability www.national.com/quality
LED Lighting www.national.com/led Feedback/Support www.national.com/feedback
Voltage References www.national.com/vref Design Made Easy www.national.com/easy
PowerWise® Solutions www.national.com/powerwise Applications & Markets www.national.com/solutions
Serial Digital Interface (SDI) www.national.com/sdi Mil/Aero www.national.com/milaero
Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic
PLL/VCO www.national.com/wireless PowerWise® Design
University
www.national.com/training
THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION
(“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY
OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO
SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,
IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS
DOCUMENT.
TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT
NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL
PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR
APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND
APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE
NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.
EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO
LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE
AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR
PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY
RIGHT.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and
whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected
to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness.
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.
Copyright© 2011 National Semiconductor Corporation
For the most current product information visit us at www.national.com
National Semiconductor
Americas Technical
Support Center
Email: support@nsc.com
Tel: 1-800-272-9959
National Semiconductor Europe
Technical Support Center
Email: europe.support@nsc.com
National Semiconductor Asia
Pacific Technical Support Center
Email: ap.support@nsc.com
National Semiconductor Japan
Technical Support Center
Email: jpn.feedback@nsc.com
www.national.com
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic."Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products Applications
Audio www.ti.com/audio Communications and Telecom www.ti.com/communications
Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers
Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps
DLP®Products www.dlp.com Energy and Lighting www.ti.com/energy
DSP dsp.ti.com Industrial www.ti.com/industrial
Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical
Interface interface.ti.com Security www.ti.com/security
Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Mobile Processors www.ti.com/omap
Wireless Connectivity www.ti.com/wirelessconnectivity
TI E2E Community Home Page e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright ©2011, Texas Instruments Incorporated
