SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r February 2012 Rev. 1.0.0 GENERAL DESCRIPTION APPLICATIONS The SPX 3940 is a 1A, accurate voltage regulator 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 respon They are fully fault protected against over current, reverse battery, and positive and negative voltage transients. x Power Supp lies x LCD Monitors x Portable Instrumentation se. - The SPX 3940 is offered in 3 - pin SOT223 and TO- 263 packages. For a 3A version, refer to the SPX29300 data sheet. x Medical and Industrial Equipments FEATURES x Guaranteed 1.5A Peak Current x 1% Output Accuracy SPX3940A x Low Quiescent Current x Low Dropout Voltage of 280mV at 1A x Extremely Tight Load and Line Regulation x Extremely Fast Transient Response x Reverse - battery Protection x Internal Thermal Protection x Internal Short Circuit Current Limit x Replacement for LM x Standard TYPICAL APPLICATION 3 940 SOT223 & TO - 263 packages DIAGRAM Fig. 1: SPX3940 Application Diagram Exar Corporation 48720 Kato Road, Fremont CA 94538 , USA ±Fixed Output Linear Regulator Tel. +1 510 668 www.exar.com - 70 00 ±Fax. +1 510 668 - 70 01 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r ABSOLUTE MAXIMUM RAT INGS 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 specification below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. OPERATING RATINGS Input Voltage VIN ................................ .................... 16V Junction Temperature Range .................... - 40°C to 1 25 °C Package s Thermal Resistance SOT- 223 Junction to Case (at T A) ..................... 15 °C/W SOT- 223 Junction to Ambient ........................ 62.3°C/W TO- 263 Junction to Case (at T A) ......................... 3°C/W TO- 263 Junction to Ambient .......................... 31.4 °C/W s Input Voltage V IN ................................ ................... 20 V1 Storage Temperature .............................. - 65°C to 150°C Lead Temperature (Soldering, 5 sec) ..................... 26 0°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 SPECIFICA TIONS Specifications with standard type are for an Operating Ambient Temperature of TA = 25°C only; limits a pplying over the full 2SHUDWLQJ -XQFWLRQ 7HPSHUDWXUH ´ UDQJH 0LQLPXP DUH GHQRWHG DQG 0D[LPXP E\ DOLPLWV ³ DUH JXDUD design, or statistical correlation. Typical values represent the most likely parametric norm at T ided A = 25°C, and are prov for reference purposes only. Unless otherwise indicated, V CIN = 6.8 µF, COUT = 10 µF, TA = 25°C . IN = V IN +1V , I OUT = 10mA, Parameter Min. Typ. Max. Units Conditions 1.782 1.755 1.764 1.737 1.8 1.8 1.8 1.8 1.818 1.845 1.836 1.863 2.475 2.437 2.450 2.412 2.5 2.5 2.5 2.5 2.525 2.563 2.550 2.588 3.267 3.217 3.234 3.184 3.3 3.3 3.3 3.3 3.333 3.383 3.366 3.416 4.950 4.875 4.900 4.825 5.0 5.0 5.0 5.0 5.050 5.125 5.100 5.175 Line Regulation 0.2 1.0 % I OUT=10mA, (V Load Regulation 0.3 1.5 % VIN = V 20 100 ppm/°C 1.8V version Output Voltage - SPX3940A (1%) Output Voltage - SPX3940 (2%) - SPX3940A (1%) V V I OUT=10mA P$, OUT$99 IN 9 2.5V version Output Voltage Output Voltag e - SPX3940 (2%) V V I OUT=10mA P$, OUT$99 IN 9 3.3V version Output Voltage - SPX3940A (1%) Output Voltage - SPX3940 (2%) Output Voltage - SPX3940A (1%) Output Voltage - SPX3940 (2%) V V I OUT=10mA P$, OUT$99 IN 9 5 .0 V version V V I OUT=10mA P$, OUT$99 IN 9 All Voltage Options ο ο் - Output Voltage temperature Coefficient Dropout Voltage 2 (except 1.8V version) Ground Current 3 I GNDDO Ground Pin Current at Dropout Current Limit Output Noise Voltage © 2012 Exar Corporation 1.5 OUT OUT 99 IN 9 9P$, OUT$ 70 200 mV 280 550 mV I OUT=100mA I OUT=1A 12 25 mA I OUT=750mA, V IN =V OUT +1V 18 mA I OUT=1A 1.2 mA VIN = 0.1V less than specified V VOUT = 0V OUT I OUT=10mA, 4 2.2 A 400 µV RMS 10Hz - 100KHz, I L=100mA, C L=10µF 26 0 µV RMS 10Hz - 100KHz, I L=100mA, C L=33µF 2/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r 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 draw n from the source is the sum of the load current to the ground current. Note 4: VIN =V OUT(NOMINAL) +1V. For example, use V - testing procedures to minimize IN =4.3V for a 3.3V regulator. Employ pulse temperature rise. BLOCK DIAGRAM Fig. 2: SPX3940 Block Diagram PIN ASSIGNMENT Fig. 3: SPX3940 Pin Assign ment © 2012 Exar Corporation 3/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r ORDERING INFORMATION Part Number SPX3940AM3 - L- 1- 8 SPX3940AM3 - L- 1- 8/TR SPX3940AM3 - L- 2- 5 SPX3940AM3 - L- 2- 5/TR SPX3940AM3 - L- 3- 3 SPX3940AM3 - L- 3- 3/TR SPX3940AM3 - L- 5- 0 SPX3940AM3 - L- 5- 0/TR SPX3940AT - L- 1- 8 SPX3940AT - L- 1- 8/TR SPX3940AT - L- 3- 3 SPX3940AT - L- 3- 3/TR SPX3940AT - L- 5- 0 SPX3940AT - L- 5- 0/TR SPX3940M3 - L- 2- 5 SPX3940M3 - L- 2- 5/TR SPX3940M3 - L- 3- 3 SPX3940M3 - L- 3- 3/TR SPX3940M3 - L- 5- 0 SPX3940M3 - L- 5- 0/TR SPX3940T - L- 3- 3 SPX3940T - L- 3- 3/TR SPX3940T - L- 5- 0 SPX3940T - L- 5- 0/TR ³<<´ <HDU ±³::´ © 2012 Exar Corporation Temperature Range Marking 3940A 18YYWWL - &7 J& XXX 3940A 25YYWWL - &7 J& XXX 3940A 33YYWWL - &7 J& XXX 3940A 50YYWWL - &7 J& XXX Package 3- pin SOT- 223 3- pin SOT- 223 3- pin SOT- 223 3- pin SOT- 223 Packing Quantity 2.5K /Tape & Reel Bulk Bulk 1.8 V Output Voltage ±1% Lead Free 2.5V Output Voltage ±1% Lead Free 3.3V Output Voltage ±1% Lead Free 5.0V Output Voltage ±1% Lead Free 1.8V Output Voltage ±1% Lead Free 3.3V Output Voltage ±1% Lead Free 5.0V Output Voltage ±1% Lead Free 2.5V Output Voltage ±2% Lead Free 3.3V Output Voltage ±2% Lead Free 5.0V Output Voltage ±2% Lead Free 3.3V Output Voltage ±2% Lead Free 5.0V Output Voltage ±2% 2.5K/Tape & Reel Bulk 2.5K/Tape & Reel Bulk 3- pin TO- 263 500/Tape & Reel SPX3940AT - 40°C 7 J& 33YYWWLX 3- pin TO- 263 500/Tape & Reel SPX3940AT - &7 J& 50YYWWLX 3- pin TO- 263 500/Tape & Reel 3940M3 - &7 J& 25YYWWL 3- pin SOT- 223 2.5K/Tape & Reel 3940M3 - &7 J& 33YYWWL 3- pin SOT- 223 2.5K/Tape & Reel 3940M3 - &7 J& 50YYWWL 3- pin SOT- 223 2.5K/Tape & Reel SPX3940T - &7 J& 33YYWWLX 3- pin TO- 263 500/Tape & Reel SPX3940T - &7 J& 33YYWWLX 3- pin TO- 263 500/Tape & Reel Bulk Bulk Bulk Bulk Bulk Bulk Bulk Bulk Note 2 Lead Free 2.5K/Tape & Reel SPX3940AT - &7 J& 18YYWWLX :RUN:H ek ±³;´ Note 1 /RW1XPEHU ±when applicable. 4/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r TYPICAL PERFORMANCE CHARACTERISTICS Schematic and BOM from Application Information section of this datasheet. Fig. 5: Load Regulation Fig. 4: Line Regulation Fig. 7: Ground Current vs Input Voltage Fig. 6: Ground Current vs Load Current Fig. 8: Ground Current vs © 2012 Exar Corporation Fig. 9: Dropout Voltage Load Current in Dropout 5/ 11 vs Load Current Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r Fig. 10 : Ground Current vs Temperature I LOAD =100mA Fig. 11 : Output Voltage vs Temperature I LOAD =100mA Fig. 12 : Ground Current vs Temperature I LOAD =500mA Fig. 13 : Ground Current vs Temperature Dropout, I LOAD =750mA Fig. 14 : Ground Current vs Temperature I LOAD =1.5A Fig. 15 : Ground Current vs Temperature Dropout, I LOAD =1.5A © 2012 Exar Corporation 6/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r Fig. 16 : Dropout Voltage vs Temperature I LOAD =750mA Fig. 17 : Dropout Voltage vs Temperature I LOAD =1.5A Fig. 18 : Enable Current vs Temperature VEN=16V © 2012 Exar Corporation Fig. 19 : Enable Threshold vs Temperature 7/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r THEORY OF OPERATION TJ = T The SPX3 940 incorporates protection against over - current faults, reversed load insertion, over temperature operation, and positive and negative transient voltage. TJ = 50 + 7.5 * (1 + 2 + 3) = 95°C T HERMAL CONSIDERATIONS The output capacitor is needed to insure stabi lity and minimize the output noise. The value of the capacitor varies with the load. However, a minimum value of 10 µF aluminum capacitor will guarantee stability over all load conditions. A tantalum capacitor is recommended if a faster load transient resp onse is needed. CAPACITOR R EQUIREMENTS If the power source has a high AC impedance, a 0.1 µF ceramic capacitor between input & ground is recommended. M INIMUM TO - 220 Design Example: L OAD CURRENT To ensure a proper behavior of the regulator under light load, a minimum load of 5mA for SPX3940 is required. Assume that V IN = 10V, V OUT = 5V, I OUT = 1.5A, T A &: LJ HA= 1°C/W, LJCH &:DQGLJ = 3°C/W. JC A + P D LJ HA LJ CH LJ JC) or Reliable operation is insured. Although the SPX3940 o ffers 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 th e best thermal flow of the component, proper mount - ing is required. Consult heatsink manufacturer for thermal resistance and design of heatsink. Where T A = ambient temperature LJHA = heatsink to ambient thermal resistance LJCH = case to heatsink thermal resistance LJJC = junction to case thermal resistance The power calculated under these condition is: PD = (V IN ±VOUT) * I OUT s Fig. 20 : Fixed Output Linear Regulator = 7.5W. And the junction temperature is calculated as © 2012 Exar Corporation 8/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r PACKAGE SPECIFICATIO N 3 - P IN SOT - 223 © 2012 Exar Corporation 9/ 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r 3 - P IN TO - 2 63 © 2012 Exar Corporation 10 / 11 Rev. 1.0.0 SP X 3 9 4 0 1 A L o w D r o p o u t V o l t a g e Re g u l a t o r REVISION HISTORY Revision A 1.0.0 Date Description 04/14 /200 6 02/29/2012 FOR FURTHER ASSISTAN Reformat of Datashee t Package drawing corrections CE Email: [email protected] Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx? EXAR CORPORATION H EADQUARTERS AND SALES O FFICES 48720 Kato Road Fremont, CA 94538 ±USA Tel.: +1 (510) 66 8- 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 XVHU¶VVSHFLILFDSSOLFDWLRQ:KLOHWKHLQIRUPDWLRQLQWKLVSXEOLFDWLRQ , is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. © 2012 Exar Corporation 11 / 11 Rev. 1.0.0