LM2575

POWER MANAGEMENT Description The LM2575/6 series switching regulators are monolithic integrated circuits designed for use in “buck” or “buck/ boost” regulator applications requiring accurate output voltages over combined variations of line, load and temperature. This unique series greatly simplifies switching power supply design. The LM2575 has a maximum output current of 1A and the LM2576 is rated for 3A. 1A & 3A Miniconverter Switching Regulators Features u Pin for pin replacement for National’s LM2575/6 u DC-to-DC buck or buck/boost converter requiring only 4 support components Fixed or adjustable voltages Preset output voltages of 3.3V, 5V and 12V Wide output voltage range, 1.23V to 35V 82% typical efficiency @ 5V out Wide input voltage range, 4V to 40V Inhibit/enable control pin Industrial temperature range TO-220 and TO-263 packages series LM2575 & LM2576 u u u u The LM2575/6 series miniconverters include a u switching regulator and compensation network all within u the same package. Just add a choke, catch diode and u two capacitors to obtain an efficient DC-to-DC converter. u The current limit and thermal shutdown features of the LM2575/6 series fully protect the device against overstress conditions. Applications u u u u Micro controller power supplies Medical equipment Industrial power supplies Instrumentation power supplies The LM2575/6 series offers an alternative to popular 3 terminal linear regulators by providing higher efficiency with reduced heatsink size. In many applications a heat sink will not be required. Typical Application Circuits LM2575 L1 D1 C IN C OUT 330µH 3A 68µF 330µF LM2576 100µH 7A 120µF 1,000µF Revision 1, January 2001 1 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Absolute Maximum Ratings Parameter Input Voltage On/Off Pi n Input Voltage Output Voltage to C ommon (Steady State) Power D i ssi pati on Thermal Resi stance Juncti on to Ambi ent TO-220 TO-263 Thermal Resi stance Juncti on to C ase TO-220 TO-263 Operati ng Juncti on Temperature Range Storage Temperature Range Lead Temperature (Solderi ng) 10 Sec. ESD Rati ng (Human Body Model) PD q JA Sy mbol VIN VON/OFF Maximum 45 -0.3 £ VON/OFF £ VIN -1 Internally Li mi ted 55 60 2.0 2.0 -40 to +125 -65 to +150 300 2 U nits V V V W °C /W q JC TJ TSTG TLEAD V ESD °C /W °C °C °C kV Electrical Characteristics Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V; IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range. Parameter Output Voltage LM2576-3.3 Sy mbol VO Test C onditions IO = 0.5A 8V to VIN Rated Min 3.23 3.20 3.14 Ty p 3.30 Max 3.37 3.40 3.47 U nits V Output Voltage LM2576-5 VO IO = 0.5A 8V to VIN Rated 4.90 4.85 4.75 5.00 5.10 5.15 5.25 V Output Voltage LM2576-12 VO IO = 0.5A 15V to VIN Rated 11.76 11.52 11.40 12.00 12.24 12.48 12.60 V Feedback Voltage LM2576-AD J, VO = 5V V FB IO = 0.5A 8V to VIN Rated 1.217 1.193 1.180 1.230 1.243 1.267 1.280 V Feedback Bi as C urrent LM2576-AD J ã 2001 Semtech Corp. IB VIN = 12V, IO = 0.5A 50 100 500 nA 2 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Electrical Characteristics (Cont.) Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V; IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range. Parameter Output Voltage LM2575-3.3 Sy mbol VO Test C onditions IO = 0.2A 8V to VIN Rated Min 3.23 3.20 3.14 Ty p 3.30 Max 3.37 3.40 3.47 U nits V Output Voltage LM2575-5 VO IO = 0.2A 8V to VIN Rated 4.90 4.85 4.75 5.00 5.10 5.15 5.25 V Output Voltage LM2575-12 VO IO = 0.2A 15V to VIN Rated 11.76 11.52 11.40 12.00 12.24 12.48 12.60 V Feedback Voltage LM2575-AD J, VO = 5V V FB IO = 0.2A 8V to VIN Rated 1.217 1.193 1.180 1.230 1.243 1.267 1.280 V Feedback Bi as C urrent LM2575-AD J Effi ci ency/Opti on 3.3V 5V 12V A D J, V O = 5 V Swi tchi ng Frequency IB VIN = 12V, IO = 0.2A 50 100 500 nA h VIN = 12V, IO = 1A (LM2575, 3A for LM2576) 77 82 % VIN = 15V, IO = 1A (LM2575, 3A for LM2576) VIN = 12V, IO = 1A (LM2575, 3A for LM2576) fSX 47 43 88 82 52 58 62 0.9 0.9 93 1.7 1.3 98 2.2 3.0 3.2 5.8 6.9 7.5 A 1.2 1.4 % A V kHz Saturati on Voltage(1) VSAT LM2575, IO = 1A LM2576, IO = 3A Max. D uty C ycle (On)(3) Peak C urrent LM2575(1) DC ICL Peak C urrent LM2576(1) ICL 4.2 3.5 ã 2001 Semtech Corp. 3 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Electrical Characteristics (Cont.) Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V; IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range. Parameter Output Leakage C urrent(2) Output = 0V Output = -1V Qui escent C urrent(2) Sy mbol Test C onditions Min Ty p Max U nits IL VIN = VIN Rated 7.5 2 30 10 12 mA IQ 5 mA Standby Qui escent C urrent (On/Off Pi n = 5V) On/Off Pi n Logi c Input Level ISTBY 50 500 µA VIH 2.2 2.4 1.4 V VIL 1.2 1.0 0.8 V On/Off Pi n Input C urrent IIH IIL VON/OFF = 5V (Off) VON/OFF = 0V (On) 12 0 30 10 µA Notes: (1) Output sourcing current, resistive load, no inductor or capacitor. (2) Feedback = VO + 1.0V. (3) Feedback = 0V. ã 2001 Semtech Corp. 4 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Pin Configurations Ordering Information D ev ice(1) LM2575T-XX LM2575S-XX.TR LM2576T-XX LM2576S-XX.TR P ackag e TO-220-5(2)(3) TO-263-5(4) TO-220-5(2)(3) TO-263-5(4) 3A C urrent 1A TO-263-5 LM2575, LM2576 Pin Function VIN OUTPUT C OMMON FE E D B A C K ON/OFF TO-220-5 1 2 3 4 5 Notes: (1) -XX = Voltage Option. Available voltages are 3.3V (-3.3), 5V (-5.0), 12V (-12), and ADJ (-ADJ), which is adjustable between 1.23V and 35V. (2) Lead bend options for TO-220-5 are: T-XX = Straight in-line; T-XX-V = Vertical Staggered; T-XX-H = Horizontal Staggered. Please refer to outline drawings at the end of this datasheet. (3) Only available in tube packaging. A tube contains 50 devices. (4) Only available in tape and reel packaging. A reel contains 800 devices. TAB i s C OMMON Block Diagram ã 2001 Semtech Corp. 5 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2575 ã 2001 Semtech Corp. 6 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2575 (Cont.) ã 2001 Semtech Corp. 7 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2575 (Cont.) ã 2001 Semtech Corp. 8 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2576 ã 2001 Semtech Corp. 9 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2576 (Cont.) ã 2001 Semtech Corp. 10 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Typical Characteristics - LM2576 (Cont.) ã 2001 Semtech Corp. 11 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Applications Information - Buck Mode LM2575 L1 D1 C IN C OUT 330µH 3A 68µF 330µF LM2576 100µH 7A 120µF 1,000µF The above component selections will be adequate for most applications for output currents from 250mA to 3A (LM2576) or 150mA to 1A (LM2575). Applications with V OUT below 5V or above 24V may require component adjustment for maximum performance; please contact factory for application assistance. 1. Device Selection. Select an appropriate device from the “Ordering Information” guide based upon voltage option and package. 2. Thermal Conditions. Most applications will not require a heatsink for the TO-220 package. Approximate power dissipation is: P= VO VO IO VSAT + 0 .02 VIN VIN VIN Schottky versus an ultra fast diode is efficiency. Schottkys will provide approximately 4% to 5% improvement for VOUTS below 12V, whereas above 12V the difference will become less significant. Breakdown rating must be in excess of VIN for margin. 4. Input Capacitor. The value shown will be adequate for most applications. Ripple voltage at the switching frequency is caused by the input capacitor supplying load current during the on time of the power switch. The use of a low ESR switching type capacitor will minimize ripple to an acceptable level. 5. Layout. Use short connections with a central point ground to prevent improper operation caused by stray inductance and ground loops. 6. Output Capacitor. Ripple voltage on VOUT is directly related to the value of COUT and the internal resistance ESR of COUT. Output noise can be lowered by increasing COUT or by selecting a capacitor with a lower ESR. ESR must be a minimum of 0.03W for the LM2576 or 0.07W for the LM2575 to maintain stability, otherwise raise the value of COUT. 12 www.semtech.com 3. Catch Diode. If the output must be capable of a sustained short, the IF rating must be above 3A for the LM2575 and 7A for the LM2576. The use of an ultra fast diode with soft recovery characteristics or a Schottky will be adequate. The major impact on the selection of a ã 2001 Semtech Corp. LM2575 & LM2576 POWER MANAGEMENT Applications Information (Cont.) 7. Switching Spikes. Switching spikes will also occur due to distributive capacitance across turns of the inductor when combined with output capacitor series inductance (ESL). Reduction to a level at or below the switching ripple can be achieved by using a post filter as shown below. Switching Spike Reduction Typical Buck Shutdown ã 2001 Semtech Corp. 13 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Applications Information (Cont.) Turn-On Delay Under Voltage Lockout Turn-On Delay With Spike Filter ã 2001 Semtech Corp. 14 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Applications Information - Inverting Buck/Boost LM2575 C IN D1 L1 C OUT IOUT 47µF 3A 100µH 2,700µF 250mA LM2576 100µF 7A 68µH 6,800µF 500mA LM2575 C IN D1 L1 C OUT IOUT 47µF 3A 100µH 470µF 100mA LM2576 100µF 7A 68µH 2,700µF 750mA Inverting buck/boost operation is a different topology of operation than buck. This difference reduces the output current capability of the device, in that the inductor must supply all of the load current during the time the power switch is off. Maximum output current is approximately: IOUT ≈ 3 .5  2    V 1 + O  VIN           Component stress requirements are very similar to the buck with a few exceptions: (1) catch diode breakdown VBR must be greater than VIN + |VOUT| (2) input capacitor is larger due to the increased peak current during switch turn on. Power dissipation is approximately:  VO PD ≈   V O + V IN    IO    VO 1 +  V IN   VO  V SAT + 0 . 02 V IN  V IN  (LM 2576 ) IOUT ≈ 1 .3  2    V 1 + O  VIN           (LM 2575 ) Please contact factory for additional assistance when using the buck/boost topology. ã 2001 Semtech Corp. 15 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Applications Information (Cont.) Inverting Buck/Boost Shutdown ã 2001 Semtech Corp. 16 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Support Components Information Pre-Wound Inductors: Hurricane Electronics Lab P.O. Box 1280 Hurricane Industrial Park Hurricane, UT 84737 (801) 635-2003 Core Source: Micro Metals, Inc. 1190 N. Hawk Circle Anaheim, CA 92807 (714) 630-7420 Capacitors: VPR Series Mallory Capacitor Co. 4760 Kentucky Avenue Indianapolis, IN 46241 (317) 856-3731 511D & 673 Series Sprague Electric Co. North Adams, MA (413) 664-4411 HFQ, HFZ Series Panasonic Industrial Co. 2 Panasonic Way Secaucus, NJ 07094 (201) 392-6142 PF, PL Series Nichicon Corp. 927 E. State Pkwy. Schaumburg, IL 60195 (708) 843-7600 LXF Series United Chemi-con 9801 West Higgins Road Rosemont, IL 60018 (708) 696-2000 Heat Sinks: AAVID Engineering Co. P.O.Box 400 One Kool Path Laconia, NH 03247 (603) 528-3400 Thermalloy, Inc. 2021 W. Valley View Lane Dallas, TX 76381 (214) 243-4321 Diodes - Catch: Ultra Fast/Soft Recovery Semtech Corporation 652 Mitchell Road Newbury Park, CA 91320 (805) 498-2111 Diodes - Schottky: Fuji/Collmer Semiconductor 14368 Proton Road Dallas, TX 76244 (800) 527-0521 Micro Quality 1000 N. Shiloh Garland, TX 76046 (214) 272-7811 ã 2001 Semtech Corp. 17 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Outline Drawing - TO-220-5 (T-XX Option) Outline Drawing - TO-220-5 (T-XX-H Option) Outline Drawing - TO-220-5 (T-XX-V Option) ã 2001 Semtech Corp. 18 www.semtech.com LM2575 & LM2576 POWER MANAGEMENT Outline Drawing - TO-263-5 Minimum Land Pattern - TO-263-5 Contact Information Semtech Corporation Power Management Products Division 652 Mitchell Rd., Newbury Park, CA 91320 Phone: (805)498-2111 FAX (805)498-3804 ã 2001 Semtech Corp. 19 www.semtech.com