S P X2 9 4 0 1A Low Dropout Voltage Regulator August 2009 Rev. 2.0.0 GENERAL DESCRIPTION The SPX2940 is a 1A, accurate voltage regulators with a low drop out voltage of 280mV (typical) at 1A. These regulators are specifically designed for low voltage applications that require a low dropout voltage and a fast transient response. They are fully fault protected against overcurrent, reverse battery, and positive and negative voltage transients. The SPX2940 is offered in 3-pin TO-220 & TO263 packages. For a 3A version, refer to the SPX29300 data sheet. APPLICATIONS • Power Supplies • LCD Monitors • Portable Instrumentation • Medical and Industrial Equipments FEATURES • Guaranteed 1.5A Peak Current • Low Quiescent Current • Low Dropout Voltage of 280mV at 1A • Extremely Tight Load and Line Regulation • Extremely Fast Transient Response • Reverse-battery Protection • Internal Thermal Protection • Internal Short Circuit Current Limit • Replacement for LM2940, MIC2940A, AS2940 • Standard TO-220 and TO-263 packages TYPICAL APPLICATION DIAGRAM Fig. 1: SPX2940 Application Diagram – Fixed Output Linear Regulator Exar Corporation 48720 Kato Road, Fremont CA 94538, USA www.exar.com Tel. +1 510 668-7000 – Fax. +1 510 668-7001 S P X2 9 4 0 1A Low Dropout Voltage Regulator ABSOLUTE MAXIMUM RATINGS OPERATING RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. Junction Temperature Range ....................-40°C to 125°C TO-220 Package Thermal Resistance, Junction to Case (at TA) .......... 4°C/W TO-263 Package Thermal Resistance, Junction to Case (at TA) .......... 4°C/W Input Voltage VIN ................................................... 16V1 Storage Temperature .............................. -65°C to 150°C Lead Temperature (Soldering, 5 sec) ..................... 260°C Note 1: Maximum positive supply voltage of 20V must be of limited duration (<100ms) and duty cycle (<1%). The maximum continuous supply voltage is 16V. ELECTRICAL SPECIFICATIONS Specifications with standard type are for an Operating Ambient Temperature of TA = 25°C only; limits applying over the full Operating Junction Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TA = 25°C, and are provided for reference purposes only. Unless otherwise indicated, VIN = VIN +1V, IOUT = 10mA, CIN = 6.8µF, COUT = 10µF, TA = 25°C. Parameter Min. Typ. Max. Units Conditions 4.850 4.750 Line Regulation 5.0 5.0 0.2 5.150 5.250 1.0 V V % Load Regulation 0.3 1.5 % 20 100 ppm/°C • 5.0V version Output Voltage ∆ ∆ - Output Voltage temperature Coefficient Dropout Voltage2 (except 1.8V version) Ground Current3 IOUT=10mA 10mA≤IOUT≤1A, 6V≤VIN≤16V IOUT=10mA, (VOUT +1V)≤VIN≤16V VIN = VOUT +1V,10mA≤IOUT≤1A 70 200 mV • 280 550 mV • IOUT=1A 12 25 mA • IOUT=750mA, VIN = VOUT +1V 18 IGNDDO Ground Pin Current at Dropout 1.2 Current Limit 1.5 Output Noise Voltage • 2.2 IOUT=100mA mA IOUT=1A mA VIN = 0.1V less than specified VOUT IOUT=10mA, A VOUT = 0V4 400 µVRMS 10Hz-100KHz, IL=100mA, CL=10µF 260 µVRMS 10Hz-100KHz, IL=100mA, CL=33µF Note 2: Dropout voltage is defined as the input to output differential when the output voltage drops to 99% of its normal value. Note 3: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current to the ground current. Note 4: VIN=VOUT(NOMINAL)+1V. For example, use VIN=4.3V for a 3.3V regulator. Employ pulse-testing procedures to minimize temperature rise. © 2009 Exar Corporation 2/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator BLOCK DIAGRAM Fig. 2: SPX2940 Block Diagram PIN ASSIGNMENT Fig. 3: SPX2940 Pin Assignment ORDERING INFORMATION Part Number Temperature Range Marking SPX2940T 50YYWWLX SPX2940U -40°C≤TJ≤+125°C 50YYWWLX SPX2940T-L-5-0/TR -40°C≤TJ≤+125°C SPX2940U-L-5-0 Package 3-pin TO-263 3-pin TO-220 Packing Quantity Note 1 500/Tape & Reel Lead Free Bulk Lead Free Note 2 5.0V Output Voltage 5.0V Output Voltage “YY” = Year – “WW” = Work Week – “X” = Lot Number © 2009 Exar Corporation 3/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator TYPICAL PERFORMANCE CHARACTERISTICS Schematic and BOM from Application Information section of this datasheet. Fig. 4: Line Regulation Fig. 5: Load Regulation Fig. 6: Ground Current vs Load Current Fig. 7: Ground Current vs Input Voltage Fig. 8: Ground Current vs Current in Dropout Fig. 9: Dropout Voltage vs Load Current © 2009 Exar Corporation 4/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator Fig. 10: Ground Current vs Temperature ILOAD=100mA Fig. 11: Output Voltage vs Temperature ILOAD=100mA Fig. 12: Ground Current vs Temperature ILOAD=500mA Fig. 13: Ground Current vs Temperature Dropout, ILOAD=750mA Fig. 14: Ground Current vs Temperature ILOAD=1.5A Fig. 15: Ground Current vs Temperature Dropout, ILOAD=1.5A © 2009 Exar Corporation 5/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator Fig. 16: Dropout Voltage vs Temperature ILOAD=750mA Fig. 17: Dropout Voltage vs Temperature ILOAD=1.5A Fig. 18: Enable Current vs Temperature VEN=16V Fig. 19: Enable Threshold vs Temperature © 2009 Exar Corporation 6/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator recommended if a response is needed. THEORY OF OPERATION The SPX2940 incorporates protection against over-current faults, reversed load insertion, over temperature operation, and positive and negative transient voltage. faster load transient If the power source has a high AC impedance, a 0.1µF ceramic capacitor between input & ground is recommended. THERMAL CONSIDERATIONS MINIMUM LOAD CURRENT Although the SPX2940 offers limiting circuitry for overload conditions, it is still necessary to insure that the maximum junction temperature is not exceeded in the application. Heat will flow through the lowest resistance path, the junction-to-case path. In order to insure the best thermal flow of the component, proper mounting is required. Since the case of the device is electrically connected to the output, the case must be electrically isolated using a thermally conductive spacer, which itself contributes some small additional thermal resistance. Consult heatsink manufacturer for thermal resistance and design of heatsink. To ensure a proper behavior of the regulator under light load, a minimum load of 5mA for SPX2940 is required. consequat eu, consequat eu, ullamcorper pretium, magna. Aenean varius turpis sed metus. Donec erat. Nunc urna pede, accumsan sed, tristique non, lobortis sit amet, pede. Fig. 20: Fixed Output Linear Regulator TO-220 Design Example: Assume that VIN = 10V, VOUT = 5V, IOUT = 1.5A, TA = 50°C/W, θHA= 1°C/W, θCH = 2°C/W, and θJC = 3°C/W. Where TA = ambient temperature θHA = heatsink to ambient thermal resistance θCH = case to heatsink thermal resistance θJC = junction to case thermal resistance The power calculated under these conditions is: PD = (VIN – VOUT) * IOUT = 7.5W. Fig. 21: Ouput Cap ESR vs IOUT And the junction temperature is calculated as TJ = TA + PD * (θHA + θCH + θJC) or TJ = 50 + 7.5 * (1 + 2 + 3) = 95°C Reliable operation is insured. CAPACITOR REQUIREMENTS The output capacitor is needed to insure stability and minimize the output noise. The value of the capacitor varies with the load. However, a minimum value of 10µF aluminum capacitor will guarantee stability over all load conditions. A tantalum capacitor is © 2009 Exar Corporation Fig. 22: 5.0VOUT PSSR VIN=10V, VOUT=5V COUT=22F, IOUT=10mA 7/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator PACKAGE SPECIFICATION 3-PIN TO-263 © 2009 Exar Corporation 8/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator 3-PIN TO-220 © 2009 Exar Corporation 9/10 Rev. 2.0.0 S P X2 9 4 0 1A Low Dropout Voltage Regulator REVISION HISTORY Revision Date F 11/03/2007 2.0.0 08/06/2009 Description Reformat of Datasheet Updated θJC values FOR FURTHER ASSISTANCE Email: [email protected] Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx? EXAR CORPORATION HEADQUARTERS AND SALES OFFICES 48720 Kato Road Fremont, CA 94538 – USA Tel.: +1 (510) 668-7000 Fax: +1 (510) 668-7030 www.exar.com NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a user’s specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. or its in all Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. © 2009 Exar Corporation 10/10 Rev. 2.0.0