Manufacturer Part NumberLM2586S-12/NOPB
ManufacturerNational Semiconductor
TypeStep-Up (Boost), Flyback, Forward Converter
LM2586S-12/NOPB datasheet

Specifications of LM2586S-12/NOPB

Internal Switch(s)YesSynchronous RectifierNo
Number Of Outputs1Voltage - Output12V
Current - Output3AFrequency - Switching100kHz ~ 200kHz
Voltage - Input4 ~ 40 VOperating Temperature-40°C ~ 125°C
Mounting TypeSurface MountPackage / CaseD²Pak, TO-263 (7 leads + tab)
For Use With551011367-051 - BOARD WEBENCH BUILD IT LM2586/88Lead Free Status / RoHS StatusLead free / RoHS Compliant
Power - Output-Other names*LM2586S-12
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General Description
The LM2586 series of regulators are monolithic integrated
circuits specifically designed for flyback, step-up (boost), and
forward converter applications. The device is available in 4
different output voltage versions: 3.3V, 5.0V, 12V, and ad-
Requiring a minimum number of external components, these
regulators are cost effective, and simple to use. Included in
the datasheet are typical circuits of boost and flyback regu-
lators. Also listed are selector guides for diodes and capaci-
tors and a family of standard inductors and flyback trans-
formers designed to work with these switching regulators.
The power switch is a 3.0A NPN device that can stand-off
65V. Protecting the power switch are current and thermal
limiting circuits, and an undervoltage lockout circuit. This IC
contains an adjustable frequency oscillator that can be pro-
grammed up to 200 kHz. The oscillator can also be synchro-
nized with other devices, so that multiple devices can oper-
ate at the same switching frequency.
Other features include soft start mode to reduce in-rush
current during start up, and current mode control for im-
proved rejection of input voltage and output load transients
and cycle-by-cycle current limiting. The device also has a
shutdown pin, so that it can be turned off externally. An
output voltage tolerance of
4%, within specified input volt-
ages and output load conditions, is guaranteed for the power
supply system.
Connection Diagrams
Bent, Staggered Leads
7-Lead TO-220 (T)
Top View
Order Number LM2586T3.3, LM2586T-5.0,
LM2586T-12 or LM2586T-ADJ
See NS Package Number TA07B
and Switchers Made Simple
are registered trademarks of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation
3A Flyback Regulator with
n Requires few external components
n Family of standard inductors and transformers
n NPN output switches 3.0A, can stand off 65V
n Wide input voltage range: 4V to 40V
n Adjustable switching frequency: 100 kHz to 200 kHz
n External shutdown capability
n Draws less than 60 µA when shut down
n Frequency synchronization
n Current-mode operation for improved transient
response, line regulation, and current limit
n Internal soft-start function reduces in-rush current during
n Output transistor protected by current limit, under
voltage lockout, and thermal shutdown
n System output voltage tolerance of
and load conditions
Typical Applications
n Flyback regulator
n Forward converter
n Multiple-output regulator
n Simple boost regulator
July 2005
4% max over line
Bent, Staggered Leads
7-Lead TO-220 (T)
Side View

LM2586S-12/NOPB Summary of contents

  • Page 1

    ... Order Number LM2586T3.3, LM2586T-5.0, LM2586T-12 or LM2586T-ADJ See NS Package Number TA07B SIMPLE SWITCHER ® and Switchers Made Simple ® are registered trademarks of National Semiconductor Corporation. © 2005 National Semiconductor Corporation 3A Flyback Regulator with ® Features n Requires few external components n Family of standard inductors and transformers n NPN output switches 3 ...

  • Page 2

    ... Connection Diagrams 7-Lead TO-263 (S) Top View Order number LM2586S-3.3, LM2586S-5.0, LM2586S-12 or LM2586S-ADJ Tape and Reel Order Number LM2586SX-3.3, LM2586SX-5.0, LM2586SX-12 or LM2586SX-ADJ See NS Package Number TS7B Package Type 7-Lead TO-220 Bent, Staggered Leads 7-Lead TO-263 7-Lead TO-263 Tape and Reel www.national.com (Continued) ...

  • Page 3

    ... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage Switch Voltage Switch Current (Note 2) Compensation Pin Voltage −0.4V ≤ V Feedback Pin Voltage ON /OFF Pin Voltage Sync Pin Voltage ...

  • Page 4

    Electrical Characteristics LM2586-5.0 (Continued) Symbol Parameters ∆V Reference Voltage REF Line Regulation G Error Amp M Transconductance A Error Amp VOL Voltage Gain LM2586-12 Symbol Parameters SYSTEM PARAMETERS Test Circuit of Figure 2 (Note 4) V Output Voltage OUT ∆V ...

  • Page 5

    Electrical Characteristics LM2586-ADJ (Continued) Symbol Parameters I Error Amp B Input Bias Current COMMON DEVICE PARAMETERS for all versions (Note 5) I Input Supply Current S I Shutdown Input S/D Supply Current V Input Supply UV Undervoltage Lockout f Oscillator ...

  • Page 6

    Electrical Characteristics LM2586-ADJ (Continued) Symbol Parameters COMMON DEVICE PARAMETERS for all versions (Note 5) θ Thermal Resistance JA θ JA θ JC θ JA θ JA θ JA θ JC Note 1: Absolute Maximum Ratings indicate limits beyond which damage ...

  • Page 7

    Typical Performance Characteristics Supply Current vs Temperature ∆Reference Voltage vs Supply Voltage Current Limit vs Temperature 01251602 01251604 01251606 7 Reference Voltage vs Temperature 01251603 Supply Current vs Switch Current 01251605 Feedback Pin Bias Current vs Temperature 01251607 www.national.com ...

  • Page 8

    Typical Performance Characteristics Switch Saturation Voltage vs Temperature Oscillator Frequency vs Temperature Error Amp Voltage Gain vs Temperature www.national.com (Continued) Switch Transconductance 01251608 Error Amp Transconductance 01251610 Short Circuit Frequency 01251612 8 vs Temperature 01251609 vs Temperature 01251611 vs Temperature ...

  • Page 9

    Typical Performance Characteristics Shutdown Supply Current vs Temperature Oscillator Frequency vs Resistance Flyback Regulator (Continued) 01251614 01251616 9 ON/OFF Pin Current vs Voltage 01251615 01251601 www.national.com ...

  • Page 10

    Test Circuits C — 100 µF, 25V Aluminum Electrolytic IN1 C — 0.1 µF Ceramic IN2 T — 22 µH, 1:1 Schott #67141450 D — 1N5820 C — 680 µF, 16V Aluminum Electrolytic OUT C — 0.47 µF Ceramic C ...

  • Page 11

    Block Diagram For Fixed Versions 3.3V 3.4k 5.0V 6.15k 12V 8.73k For Adj. Version R1 = Short (0Ω), R2 = Open Flyback Regulator Operation The ...

  • Page 12

    Flyback Regulator Operation As shown in Figure 4, the LM2586 can be used as a flyback regulator by using a minimum number of external components. The switching waveforms of this regulator are shown in Figure 5. Typical Performance Characteristics observed ...

  • Page 13

    Typical Performance Characteristics FIGURE 6. V Typical Flyback Regulator Applications Figure 7 through Figure 12 show six typical flyback applica- tions, varying from single output to triple output. Each draw- ing contains the part number(s) and manufacturer(s) for every component ...

  • Page 14

    Typical Flyback Regulator Applications www.national.com (Continued) FIGURE 8. Single-Output Flyback Regulator FIGURE 9. Single-Output Flyback Regulator 14 01251628 01251629 ...

  • Page 15

    Typical Flyback Regulator Applications (Continued) FIGURE 10. Dual-Output Flyback Regulator FIGURE 11. Dual-Output Flyback Regulator 15 01251630 01251631 www.national.com ...

  • Page 16

    Typical Flyback Regulator Applications TRANSFORMER SELECTION (T) Figure 13 lists the standard transformers available for fly- back regulator applications. Included in the table are the turns ratio(s) for each transformer, as well as the output voltages, input voltage ranges, and ...

  • Page 17

    Typical Flyback Regulator Applications Transformer Type Coilcraft (Note Coilcraft (Note 16) T5 Q4338-B Q4437-B T6 Q4339-B Q4438-B T7 S6000-A S6057-A Note 16: Coilcraft Inc., Phone: (800) 322-2645 1102 Silver Lake Road, Cary, IL 60013 Fax: (708) 639-1469 European Headquarters, 21 ...

  • Page 18

    Typical Flyback Regulator Applications (Continued) T7 Top View FIGURE 19. Coilcraft S6057-A (Surface Mount) T6 Top View FIGURE 20. Coilcraft Q4438-B (Surface Mount) T7 Top View FIGURE 21. Pulse PE-68482 T6 Top View FIGURE 22. Pulse PE-68414 (Surface Mount) www.national.com ...

  • Page 19

    Typical Flyback Regulator Applications T6 Top View FIGURE 28. Schott 67140900 T5 Top View FIGURE 29. Schott 67140890 (Continued) T7 01251647 Top View FIGURE 27. Schott 26606 Step-Up (Boost) Regulator Operation Figure 30 shows the LM2586 used as a step-up ...

  • Page 20

    Step-Up (Boost) Regulator Operation By adding a small number of external components (as shown in Figure 30), the LM2586 can be used to produce a regulated output voltage that is greater than the applied input www.national.com (Continued) FIGURE 30. 12V ...

  • Page 21

    Typical Performance Characteristics A: Switch Voltage,10V/div B: Switch Current, 2A/div C: Inductor Current, 2A/div D: Output Ripple Voltage,100 mV/div, AC-Coupled FIGURE 32. V Typical Boost Regulator Applications Figures 33, 35 through Figure 37 show four typical boost applications — one ...

  • Page 22

    Typical Boost Regulator Applications Figure 34 contains a table of standard inductors, by part number and corresponding manufacturer, for the fixed out- put regulator of Figure 33. Coilcraft (Note 20) DO3316-153 Note 20: Coilcraft Inc., Phone: (800) 322-2645 1102 Silver ...

  • Page 23

    Typical Boost Regulator Applications (Continued) FIGURE 35. +12V to +24V Boost Regulator FIGURE 36. +24V to +36V Boost Regulator 23 01251655 01251656 www.national.com ...

  • Page 24

    Typical Boost Regulator Applications Note 24: The LM2586 will require a heat sink in these applications. The size of the heat sink will depend on the maximum ambient temperature. To calculate the thermal resistance of the IC and the size ...

  • Page 25

    Application Hints (Continued) R (kΩ) Frequency (kHz) SET Open 100 200 125 47 150 33 175 22 200 FIGURE 39. Frequency Setting Resistor Guide FIGURE 40. Frequency Synchronization FREQUENCY SYNCHRONIZATION Another feature of the LM2586 is the ability to synchronize ...

  • Page 26

    Application Hints (Continued) with an external current limit circuit. The external limit should be set to the maximum switch current of the device, which is 3A flyback regulator application (Figure 43), using the stan- dard transformers, the LM2586 ...

  • Page 27

    Application Hints (Continued) range in value between 10Ω and 1 kΩ, and the capacitor will vary from 0.001 µF to 0.1 µF. Adding a snubber will (slightly) reduce the efficiency of the overall circuit. The other method to reduce or ...

  • Page 28

    ... To further simplify the flyback regulator design procedure, National Semiconductor is making available computer de- sign software to be used with the Simple Switcher switching regulators. Switchers Made Simple is available ⁄ 2 National Semiconductor sales office in your area or the National (1-800-272-9959). is the output voltage, LOAD I is the sum of the LOAD ...

  • Page 29

    ... Physical Dimensions inches (millimeters) unless otherwise noted LM2586SX-5.0, LM2586SX-12 or LM2586SX-ADJ Order Number LM2586T-3.3, LM2586T-5.0, LM2586T-12 or LM2586T-ADJ NS Package Number TA07B Order Number LM2586S-3.3, LM2586S-5.0, LM2586S-12 or LM2586S-ADJ Tape and Reel Order Number LM2586SX-3.3, NS Package Number TS7B 29 www.national.com ...

  • Page 30

    ... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...