LM2941/LM2941C 1A Low Dropout Adjustable Regulator and the load. Familiar regulator features such as short circuit and thermal overload protection are also provided. 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 differential 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 therefore only 30mA. Higher quiescent currents only exist when the regulator is in the dropout mode (VIN - VOUT 3V). Designed also 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 Features LLP space saving package 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 P+ Product Enhancement tested TTL, CMOS compatible ON/OFF switch Connection Diagram and Ordering Information TO-220 Plastic Package TO-263 Surface-Mount Package 882309 882302 Top View Order Number LM2941T or LM2941CT See NS Package Number TO5A 882308 Order Number LM2941S, LM2941SX or LM2941CS, LM2941CSX See NS Package Number TS5B 16-Lead Ceramic Dual-in-Line Package 16-Lead Ceramic Surface Mount Package 8-Lead LLP Surface Mount Package 882331 Top View Order Number LM2941J/883 LM2941J-QMLV, 5962-9166701QEA See NS Package Number J16A 882332 Top View Order Number LM2941WG/883 LM2941WG-QMLV, 5962-9166701QYA See NS Package Number WG16A 882333 Top View Ordering Number LM2941LD, LM2941LDX See NS Package Number LDC08A Note: Pin 2 & 7 are fused to center DAP (c) 2007 National Semiconductor Corporation 8823 www.national.com LM2941/LM2941C 1A Low Dropout Adjustable Regulator November 7, 2007 LM2941/LM2941C TO-263 (S) Package ESD Rating (Note 2) Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Operating Ratings Input Voltage (Survival Voltage, 100ms) LM2941T, LM2941S, LM2941LD 60V LM2941CT, LM2941CS 45V Internal Power Dissipation (Note 4) Internally Limited Maximum Junction Temperature 150C Storage Temperature Range Maximum Input Voltage Temperature Range 26V -40C TJ 125C LM2941T 0C TJ 125C LM2941CT -40C TJ 125C LM2941S -65C TJ +150C Lead Temperature (Soldering, 10 seconds) TO-220 (T) Package 260C 2 kV 0C TJ 125C LM2941CS -55C TJ 125C LM2941J -55C TJ 125C LM2941WG 260C -40C TJ 125C LM2941LD Electrical Characteristics--LM2941T, LM2941S, LM2941J, LM2941WG, LM2941LD 5V VO 20V, VIN = VO + 5V, CO = 22F, unless otherwise specified. Specifications in standard typeface apply for TJ = 25C, while those in boldface type apply over the full Operating Temperature Range. Parameter Conditions Typ LM2941J LM2941WG Limit (Notes 3, 5) LM2941T LM2941S LM2941LD Limit (Note 6) Units (Limits) 1.275 1.237/1.211 1.237/1.211 V(min) Reference Voltage 5mA IO 1A (Note 7) 1.313/1.339 1.313/1.339 V(max) Line Regulation VO + 2V VIN 26V, IO = 5mA 4 10/10 10/10 mV/V(max) Load Regulation 50mA IO 1A 7 10/10 10/10 mV/V(max) Output Impedance 100 mADC and 20 mArms 7 m/V fO = 120Hz Quiescent Current VO + 2V VIN < 26V, IO = 5mA VIN = VO + 5V, IO = 1A 10 15/20 15/20 mA(max) 30 45/60 45/60 mA(max) RMS Output Noise, % of VOUT 10Hz-100kHz IO = 5mA 0.003 Ripple Rejection fO = 120Hz, 1 Vrms, IL = 100mA 0.005 Long Term Stability Dropout Voltage % 0.02/0.04 0.02/0.04 0.4 %/V(max) %/1000 Hr IO = 1A 0.5 0.8/1.0 0.8/1.0 V(max) IO = 100mA 110 200/200 200/200 mV(max) Short Circuit Current VIN Max = 26V (Note 8) 1.9 1.6/1.3 1.6 A(min) Maximum Line VO Max 1V Above Nominal VO 75 60/60 60/60 V(min) Transient RO = 100, T 100ms Maximum Operational Input Voltage 31 26/26 26/26 VDC Reverse Polarity DC Input RO = 100, VO -0.6V Voltage -30 -15/-15 -15/-15 V(min) Reverse Polarity Transient T 100ms, RO = 100 Input Voltage -75 -50/-50 -50/-50 V(min) ON/OFF Threshold Voltage ON IO 1A 1.30 0.80/0.80 0.80/0.80 V(max) ON/OFF Threshold Voltage OFF IO 1A 1.30 2.00/2.00 2.00/2.00 V(min) ON/OFF Threshold Current VON/OFF = 2.0V, IO 1A 50 100/300 100/300 A(max) www.national.com 2 5V VO 20V, VIN = VO + 5V, CO = 22F, unless otherwise specified. Specifications in standard typeface apply for TJ = 25C, while those in boldface type apply over the full Operating Temperature Range. Parameter Conditions Reference Voltage 5mA IO 1A (Note 7) Line Regulation Load Regulation Output Impedance Typ Limit (Note 6) Units (Limits) 1.275 1.237/1.211 V(min) 1.313/1.339 V(max) VO + 2V VIN 26V, IO = 5mA 4 10 mV/V(max) 50mA IO 1A 7 10 mV/V(max) 100 mADC and 20 mArms 7 m/V fO = 120Hz Quiescent Current VO + 2V VIN < 26V, IO = 5mA VIN = VO + 5V, IO = 1A 10 15 mA(max) 30 45/60 mA(max) RMS Output Noise, % of VOUT 10Hz-100kHz IO = 5mA 0.003 Ripple Rejection fO = 120Hz, 1 Vrms, IL = 100mA 0.005 Long Term Stability Dropout Voltage % 0.02 0.4 %/V(max) %/1000 Hr IO = 1A 0.5 0.8/1.0 V(max) IO = 100mA 110 200/200 mV(max) Short Circuit Current VIN Max = 26V (Note 8) 1.9 1.6 A(min) Maximum Line VO Max 1V Above Nominal VO 55 45 V(min) Transient RO = 100, T 100ms Maximum Operational Input Voltage 31 26 VDC Reverse Polarity DC Input Voltage RO = 100, VO -0.6V -30 -15 V(min) Reverse Polarity Transient Input Voltage T 100ms, RO = 100 -55 -45 V(min) ON/OFF Threshold Voltage ON IO 1A 1.30 0.80 V(max) ON/OFF Threshold Voltage OFF IO 1A 1.30 2.00 V(min) ON/OFF Threshold Current VON/OFF = 2.0V, IO 1A 50 100 A(max) Thermal Performance Thermal Resistance Junction-to-Case 5-Lead TO-220 3 C/W 5-Lead TO-263 3 C/W Thermal Resistance Junction-to-Ambient 5-Lead TO-220 53 C/W 5-Lead TO-263 73 C/W 8-Lead LLP (Note 4) 35 C/W Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions for which the device is intended to be functional, but device parameter specifications may not be guaranteed under these conditions. For guaranteed specifications and test conditions, see the Electrical Characteristics. Note 2: The Human Body Model (HBM) is a 100 pF capacitor discharged through a 1.5k resistor into each pin. Test method is per JESD22-A114. Note 3: A military RETS specification available upon request. For more information about military-aerospace products, see the Mil-Aero web page at http:// www.national.com/appinfo/milaero/index.html. Note 4: The maximum power dissipation is a function of TJ(max), JA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(max) - TA)/JA. If this dissipation is exceeded, the die temperature will rise above 150C and the LM2941 will go into thermal shutdown. If the TO-263 package is used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the package: Using 0.5 square inches of copper area, JA is 50C/W; with 1 square inch of copper area, JA is 37C/W; and with 1.6 or more square inches of copper area, JA is 32C/W. Thermal performance for the LLP package was obtained using a JESD51-7 board with six vias, using no airflow and an ambient temperature of 22C. The value JA for the LLP package is specifically dependent on PCB trace area, trace material, and the number of layers and thermal vias. For improved thermal resistance and power dissipation for the LLP package, refer to Application Note AN-1187. It is recommended that 6 vias be placed under the center pad to improve thermal performance. Note 5: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (boldface type). All limits are used to calculate Outgoing Quality Level, and are 100% production tested. 3 www.national.com LM2941/LM2941C Electrical Characteristics--LM2941CT, LM2941CS LM2941/LM2941C Note 6: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (boldface type). All room temperature limits are 100% production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. Note 7: The output voltage range is 5V to 20V and is determined by the two external resistors, R1 and R2. See Typical Application Circuit. Note 8: Output current capability will decrease with increasing temperature, but will not go below 1A at the maximum specified temperatures. Typical Performance Characteristics Dropout Voltage Dropout Voltage vs. Temperature 882312 882311 Output Voltage Quiescent Current vs. Temperature 882313 882314 Quiescent Current Quiescent Current 882315 www.national.com 882316 4 LM2941/LM2941C Line Transient Response Load Transient Response 882318 882317 Ripple Rejection Output Impedance 882319 882320 Low Voltage Behavior Low Voltage Behavior 882321 882322 5 www.national.com LM2941/LM2941C Output Capacitor ESR Output at Voltage Extremes 882324 882323 Output at Voltage Extremes Peak Output Current 882325 882326 Maximum Power Dissipation (TO-220) Maximum Power Dissipation (TO-3) 882328 882327 www.national.com 6 LM2941/LM2941C Maximum Power Dissipation (TO-263) (Note 4) 882329 Definition of Terms Dropout Voltage: The input-voltage differential at which the circuit ceases to regulate against further reduction in input voltage. Measured when the output voltage has dropped 100mV from the nominal value obtained at (VOUT + 5V) input, dropout voltage is dependent upon load current and junction temperature. Input Voltage: The DC voltage applied to the input terminals with respect to ground. Input-Output Differential: The voltage difference between the unregulated input voltage and the regulated output voltage for which the regulator will operate. Line Regulation: The change in output voltage for a change in the input voltage. The measurement is made under conditions of low dissipation or by using pulse techniques such that the average chip temperature is not significantly affected. Load Regulation: The change in output voltage for a change in load current at constant chip temperature. Long Term Stability: Output voltage stability under accelerated life-test conditions after 1000 hours with maximum rated voltage and junction temperature. Output Noise Voltage: The rms AC voltage at the output, with constant load and no input ripple, measured over a specified frequency range. Quiescent Current: That part of the positive input current that does not contribute to the positive load current. The regulator ground lead current. Ripple Rejection: The ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage. Temperature Stability of VO: The percentage change in output voltage for a thermal variation from room temperature to either temperature extreme. Typical Applications 5V to 20V Adjustable Regulator 882303 Note: Using 1k 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. 7 www.national.com LM2941/LM2941C * Required if regulator is located far from power supply filter. ** COUT must be at least 22F 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 882306 *** To assure shutdown, select Resistor R3 to guarantee at least 300A of pull-up current when S1 is open. (Assume 2V at the ON/OFF pin.) www.national.com 8 LM2941/LM2941C Equivalent Schematic Diagram 882301 9 www.national.com LM2941/LM2941C Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM2941J/883 LM2941J-QMLV, 5962-9166701QEA NS Package Number J16A Order Number LM2941WG/883 LM2941WG-QMLV, 5962-9166701QYA NS Package Number WG16A www.national.com 10 LM2941/LM2941C Order Number LM2941T or LM2941CT NS Package Number T05A TO-263 5-Lead Plastic Surface Mount Package Order Number LM2941S, LM2941SX, LM2941CS or LM2941CSX NS Package Number TS5B 11 www.national.com LM2941/LM2941C 8-Lead LLP Surface Mount Package Order Number LM2941LD, LM2941LDX NS Package Number LDC08A www.national.com 12 LM2941/LM2941C Notes 13 www.national.com LM2941/LM2941C 1A Low Dropout Adjustable Regulator Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless 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(c) 2007 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530-85-86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +49 (0) 870 24 0 2171 Francais Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560