LM2941/LM2941C 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 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 30 mA. 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 and the load. Familiar regulator features such as short circuit and thermal overload protection are also provided. Features n n n n n n n n n 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 16-Lead Ceramic Dual-in-Line Package DS008823-2 Front View Order Number LM2941T or LM2941CT See NS Package Number TO5A DS008823-31 TO-263 Surface-Mount Package Top View Order Number LM2941J/883 5962-9166701QEA See NS Package Number J16A 16-Lead Ceramic Surface Mount Package DS008823-8 DS008823-9 Order Number LM2941S or LM2941CS See NS Package Number TS5B DS008823-32 Front View Order Number LM2941WG/883 5962-9166701QYA See NS Package Number WG16A © 1999 National Semiconductor Corporation DS008823 www.national.com LM2941/LM2941C 1A Low Dropout Adjustable Regulator June 1999 Absolute Maximum Ratings (Note 1) TO-263 (S) Package ESD susceptibility to be determined. If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. 260˚C Operating Ratings Input Voltage (Survival Voltage, ≤ 100 ms) LM2941T, LM2941S 60V LM2941CT, LM2941CS 45V 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) TO-220 (T) Package 260˚C Maximum Input Voltage Temperature Range LM2941T LM2941CT LM2941S LM2941CS LM2941J LM2941WG 26V −40˚C 0˚C −40˚C 0˚C −55˚C −55˚C ≤ ≤ ≤ ≤ ≤ ≤ TJ TJ TJ TJ TJ TJ ≤ ≤ ≤ ≤ ≤ ≤ 125˚C 125˚C 125˚C 125˚C 125˚C 125˚C Electrical Characteristics — LM2941T, LM2941S, LM2941J, LM2941WG 5V ≤ VO ≤ 20V, VIN = VO + 5V, CO = 22 µF, unless otherwise specified. Specifications in standard typeface apply for TJ = 25˚C, while those in boldface type apply over the full Operating Temperature Range. Parameter Reference Voltage Conditions Typ 5 mA ≤ IO ≤ 1A (Note 6) 1.275 LM2941J LM2941WG Limit (Note 2) (Note 4) LM2941T LM2941S Limit (Note 5) Units (Limits) 1.237/1.211 1.237/1.211 V(min) 1.313/1.339 1.313/1.339 V(max) Line Regulation VO + 2V ≤ VIN ≤ 26V, IO = 5 mA 4 10/10 10/10 mV/V(max) Load Regulation 50 mA ≤ IO ≤ 1A 7 10/10 10/10 mV/V(max) Output Impedance 100 mADC and 20 mArms fO = 120 Hz 7 Quiescent Current VO + 2V ≤ VIN < 26V, IO = 5 mA VIN = VO + 5V, IO = 1A RMS Output Noise, 10 15/20 15/20 mA(max) 30 45/60 45/60 mA(max) 10 Hz–100 kHz IO = 5 mA 0.003 % of VOUT Ripple Rejection fO = 120 Hz, 1 Vrms, IL = 100 mA 0.005 Long Term Stability Dropout Voltage Short Circuit Current Maximum Line Transient mΩ/V % 0.02/0.04 0.02/0.04 IO = 1A IO = 100 mA VIN max = 26V (Note 7) VO max 1V above nominal VO RO = 100Ω, T ≤ 100 ms Maximum Operational Input Voltage %/V(max) %/1000 Hr 0.4 0.5 0.8/1.0 0.8/1.0 V(max) 110 200/200 200/200 mV(max) 1.9 1.6/1.3 1.6 A(min) 75 60/60 60/60 V(min) 31 26/26 26/26 VDC −30 −15/−15 −15/−15 V(min) −75 −50/−50 −50/−50 V(min) Reverse Polarity DC Input Voltage RO = 100Ω, VO ≥ −0.6V Reverse Polarity Transient Input Voltage T ≤ 100 ms, RO = 100Ω 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 µA(max) www.national.com 2 Electrical Characteristics — LM2941CT, LM2941CS 5V ≤ VO ≤ 20V, VIN = VO + 5V, CO = 22 µF, unless otherwise specified. Specifications in standard typeface apply for TJ = 25˚C, while those in boldface type apply over the full Operating Temperature Range. Parameter Reference Voltage Conditions Typ 5 mA ≤ IO ≤ 1A (Note 6) 1.275 Limit Units (Note 5) (Limits) 1.237/1.211 V(min) 1.313/1.339 V(max) Line Regulation VO + 2V ≤ VIN ≤ 26V, IO = 5 mA 4 10 mV/V(max) Load Regulation 50 mA ≤ IO ≤ 1A 7 10 mV/V(max) Output Impedance 100 mADC and 20 mArms fO = 120 Hz 7 Quiescent Current VO + 2V ≤ VIN < 26V, IO = 5 mA VIN = VO + 5V, IO = 1A RMS Output Noise, 10 15 mA(max) 30 45/60 mA(max) 0.003 % of VOUT 10 Hz–100 kHz IO = 5 mA Ripple Rejection fO = 120 Hz, 1 Vrms, IL = 100 mA 0.005 Long Term Stability Dropout Voltage Short Circuit Current Maximum Line Transient mΩ/V % 0.02 IO = 1A IO = 100 mA VIN max = 26V (Note 7) VO max 1V above nominal VO RO = 100Ω, T ≤ 100 ms Maximum Operational Input Voltage %/V(max) %/1000 Hr 0.4 0.5 0.8/1.0 V(max) 110 200/200 mV(max) 1.9 1.6 A(min) 55 45 V(min) 31 26 VDC −30 −15 V(min) −55 −45 V(min) Reverse Polarity DC Input Voltage RO = 100Ω, VO ≥ −0.6V Reverse Polarity Transient Input Voltage T ≤ 100 ms, RO = 100Ω 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 µA(max) 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: 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 3: The maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any ambient temperature is PD = (TJ(max) − TA)/θJA. If this dissipation is exceeded, the die temperature will rise above 150˚C and the LM2941 will go into thermal shutdown. For the LM2941T and LM2941CT, the junction-to-ambient thermal resistance (θJA) is 53˚C/W, and the junction-to-case thermal resistance (θJC) is 3˚C/W. For the LM2941K, θJA is 35˚C/W and θJC is 4˚C/W. The junction-to-ambient thermal resistance of the TO-263 is 73˚C/W, and junction-to-case thermal resistance, θJC is 3˚C. 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, θJA is 50˚C/W; with 1 square inch of copper area, θJA is 37˚C/W; and with 1.6 or more square inches of copper area, θJA is 32˚C/W. Note 4: 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. Note 5: 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 6: The output voltage range is 5V to 20V and is determined by the two external resistors, R1 and R2. See Typical Application Circuit. Note 7: Output current capability will decrease with increasing temperature, but will not go below 1A at the maximum specified temperatures. 3 www.national.com Typical Performance Characteristics Dropout Voltage Dropout Voltage vs Temperature Output Voltage DS008823-11 DS008823-13 DS008823-12 Quiescent Current vs Temperature Quiescent Current Quiescent Current DS008823-16 DS008823-15 DS008823-14 Line Transient Response Load Transient Response DS008823-18 DS008823-17 Ripple Rejection Output Impedance DS008823-19 www.national.com DS008823-20 4 Typical Performance Characteristics Low Voltage Behavior (Continued) Low Voltage Behavior DS008823-21 Output at Voltage Extremes Output Capacitor ESR DS008823-22 Output at Voltage Extremes DS008823-23 Peak Output Current DS008823-26 DS008823-24 Maximum Power Dissipation (TO-220) DS008823-25 Maximum Power Dissipation (TO-3) Maximum Power Dissipation (TO-263) (Note 3) DS008823-28 DS008823-27 DS008823-29 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. 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 100 mV 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. 5 www.national.com Definition of Terms Temperature Stability of VO: The percentage change in output voltage for a thermal variation from room temperature to either temperature extreme. (Continued) 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. Typical Applications 5V to 20V Adjustable Regulator DS008823-3 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. * Required if regulator is located far from power supply filter. ** COUT must be at least 22 µF 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 DS008823-6 *** To assure shutdown, select Resistor R3 to guarantee at least 300 µA of pull-up current when S1 is open. (Assume 2V at the ON/OFF pin.) www.national.com 6 Equivalent Schematic Diagram DS008823-1 7 www.national.com Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM2941J/883 5962-9166701QEA NS Package Number J16A Order Number LM2941WG/883 5962-9166701QYA NS Package Number WG16A www.national.com 8 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Order Number LM2941T or LM2941CT NS Package Number T05A 9 www.national.com LM2941/LM2941C 1A Low Dropout Adjustable Regulator Physical Dimensions inches (millimeters) unless otherwise noted (Continued) TO-263 5-Lead Plastic Surface Mount Package Order Number LM2941S or LM2941CS NS Package Number TS5B LIFE SUPPORT POLICY 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 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. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: [email protected] www.national.com National Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Français Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80 2. A critical component is any component of 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. 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