lm2587sx-5.0

Manufacturer Part Numberlm2587sx-5.0
DescriptionSimple Switcher 5a Flyback Regulator
ManufacturerNational Semiconductor Corporation
lm2587sx-5.0 datasheet
 


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LM2587
SIMPLE SWITCHER
General Description
The LM2587 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-
justable.
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 5.0A 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 a 100 kHz fixed-frequency internal oscillator that
permits the use of small magnetics. Other features include
soft start mode to reduce in-rush current during start up,
current mode control for improved rejection of input voltage
and output load transients and cycle-by-cycle current limit-
ing. An output voltage tolerance of
input voltages and output load conditions, is guaranteed for
the power supply system.
Flyback Regulator
Ordering Information
Package Type
5-Lead TO-220 Bent, Staggered Leads
5-Lead TO-263
5-Lead TO-263 Tape and Reel
SIMPLE SWITCHER
®
and Switchers Made Simple
®
are registered trademarks of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
5A Flyback Regulator
®
Features
n Requires few external components
n Family of standard inductors and transformers
n NPN output switches 5.0A, can stand off 65V
n Wide input voltage range: 4V to 40V
n Current-mode operation for improved transient
response, line regulation, and current limit
n 100 kHz switching frequency
n Internal soft-start function reduces in-rush current during
start-up
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 Multiple-output regulator
n Simple boost regulator
±
4%, within specified
n Forward converter
NSC Package
Drawing
T05D
LM2587T-3.3, LM2587T-5.0, LM2587T-12, LM2587T-ADJ
TS5B
LM2587S-3.3, LM2587S-5.0, LM2587S-12, LM2587S-ADJ
TS5B
LM2587SX-3.3, LM2587SX-5.0, LM2587SX-12,
LM2587SX-ADJ
DS012316
February 2004
±
4% max over line
01231601
Order Number
www.national.com

lm2587sx-5.0 Summary of contents

  • Page 1

    ... Flyback regulator n Multiple-output regulator n Simple boost regulator ± 4%, within specified n Forward converter NSC Package Drawing T05D LM2587T-3.3, LM2587T-5.0, LM2587T-12, LM2587T-ADJ TS5B LM2587S-3.3, LM2587S-5.0, LM2587S-12, LM2587S-ADJ TS5B LM2587SX-3.3, LM2587SX-5.0, LM2587SX-12, LM2587SX-ADJ DS012316 February 2004 ± 4% max over line 01231601 Order Number www.national.com ...

  • Page 2

    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 Feedback Pin Voltage Storage Temperature Range Lead Temperature ...

  • Page 3

    LM2587-5.0 Electrical Characteristics Symbol Parameters Voltage V ∆V Reference Voltage V REF Line Regulation G Error Amp I M COMP Transconductance V A Error Amp V VOL Voltage Gain R LM2587-12 Electrical Characteristics Specifications with standard type face are for ...

  • Page 4

    LM2587-ADJ Electrical Characteristics Symbol Parameters ∆V Reference Voltage V REF Line Regulation G Error Amp I M Transconductance V A Error Amp V VOL Voltage Gain R I Error Amp V B Input Bias Current All Output Voltage Versions Electrical ...

  • Page 5

    All Output Voltage Versions Electrical Characteristics Symbol Parameters θ S Package, Junction to Ambient (Note 12) JA θ S Package, Junction to Ambient (Note 13) JA θ S Package, Junction to Ambient (Note 14) JA θ S Package, Junction to ...

  • Page 6

    Typical Performance Characteristics ∆Reference Voltage vs Supply Voltage Current Limit vs Temperature Switch Saturation Voltage vs Temperature www.national.com (Continued) 01231650 01231652 Switch Transconductance 01231654 6 Supply Current vs Switch Current 01231651 Feedback Pin Bias Current vs Temperature 01231653 vs Temperature ...

  • Page 7

    Typical Performance Characteristics Oscillator Frequency vs Temperature Error Amp Voltage Gain vs Temperature Connection Diagrams Bent, Staggered Leads 5-Lead TO-220 (T) Top View 5-Lead TO-263 (S) Top View 01231605 (Continued) 01231656 01231658 01231603 Order Number LM2587T-3.3, LM2587T-5.0, LM2587T-12 or LM2587T-ADJ ...

  • Page 8

    Block Diagram For Fixed Versions3.3V 3.4k 2k5V 6.15k 2k12V 8.73k 1kFor Adj. VersionR1 = Short (0Ω), R2 = Open Test Circuits C — 100 µF, 25V Aluminum ElectrolyticC ...

  • Page 9

    Test Circuits (Continued) C — 100 µF, 25V Aluminum ElectrolyticC — 0.1 µF CeramicL — 15 µH, Renco #RL-5472-5D — 1N5820C IN1 IN2 ElectrolyticC — 0.47 µF CeramicR — 2kFor 12V Devices Short (0Ω) and R ...

  • Page 10

    Flyback Regulator Operation The LM2587 is ideally suited for use in the flyback regulator topology. The flyback regulator can produce a single output voltage, such as the one shown in Figure 4, or multiple output voltages. In Figure 4, the ...

  • Page 11

    Typical Performance Characteristics A: Switch Voltage, 10 V/divB: Switch Current, 5 A/divC: Output Rectifier Current, 5 A/divD: Output Ripple Voltage, 100 mV/div AC-Coupled Horizontal: 2 µs/div Typical Flyback Regulator Applications Figures 11, 12 show six typical flyback ...

  • Page 12

    Typical Flyback Regulator Applications www.national.com (Continued) FIGURE 7. Single-Output Flyback Regulator FIGURE 8. Single-Output Flyback Regulator 12 01231613 01231614 ...

  • Page 13

    Typical Flyback Regulator Applications (Continued) FIGURE 9. Single-Output Flyback Regulator FIGURE 10. Dual-Output Flyback Regulator 13 01231615 01231616 www.national.com ...

  • Page 14

    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 15

    Typical Flyback Regulator Applications Applications Figure 7 Transformers T1 V 4V– 3.3V OUT1 I (Max) 1.8A OUT1 OUT2 I (Max) OUT2 OUT3 I (Max) OUT3 N 3 Transformer Type Coilcraft (Note ...

  • Page 16

    Typical Flyback Regulator Applications (Continued) T3 Top View FIGURE 17. Coilcraft Q4343-B T4 Top View FIGURE 18. Coilcraft Q4344-B T1 Top View FIGURE 19. Coilcraft Q4435-B (Surface Mount) www.national.com 01231632 FIGURE 20. Coilcraft Q4436-B 01231633 FIGURE 21. Pulse PE-68411 01231634 ...

  • Page 17

    Typical Flyback Regulator Applications (Continued) T3 Top View FIGURE 23. Pulse PE-68421 (Surface Mount) T4 Top View FIGURE 24. Pulse PE-68422 (Surface Mount) T1 Top View FIGURE 25. Renco RL-5530 FIGURE 26. Renco RL-5531 01231638 FIGURE 27. Renco RL-5534 01231639 ...

  • Page 18

    Typical Flyback Regulator Applications (Continued) T2 Top View FIGURE 30. Schott 67140860 T3 Top View FIGURE 31. Schott 67140920 www.national.com 01231644 FIGURE 32. Schott 67140930 01231645 18 T4 01231647 Top View ...

  • Page 19

    Step-Up (Boost) Regulator Operation Figure 33 shows the LM2587 used as a step-up (boost) regulator. This is a switching regulator that produces an output voltage greater than the input supply voltage. A brief explanation of how the LM2587 Boost Regulator ...

  • Page 20

    Typical Performance Characteristics Typical Boost Regulator Applications Figure 36 and Figures 38, 39 and Figure 40 show four typical boost applications) — one fixed and three using the adjust- able version of the LM2587. Each drawing contains the part Figure ...

  • Page 21

    Typical Boost Regulator Applications *The LM2587 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 of the ...

  • Page 22

    Application Hints PROGRAMMING OUTPUT VOLTAGE (SELECTING R AND Referring to the adjustable regulator in Figure 41, the output voltage is programmed by the resistors R following formula where ...

  • Page 23

    Application Hints (Continued) In addition, a small bypass capacitor is required due to the noise generated by the input current pulses. To eliminate the noise, insert a 1.0 µF ceramic capacitor between V ground as close as possible to the ...

  • Page 24

    Application Hints (Continued) OUTPUT VOLTAGE LIMITATIONS The maximum output voltage of a boost regulator is the maximum switch voltage minus a diode drop flyback regulator, the maximum output voltage is determined by the turns ratio, N, and the ...

  • Page 25

    Application Hints (Continued) 4) LM2587 package thermal resistances θ in the Electrical Characteristics). Total power dissipated ( the LM2587 can be estimated D as follows: Boost the minimum input voltage OUT N is the ...

  • Page 26

    Physical Dimensions unless otherwise noted www.national.com inches (millimeters) Order Number LM2587T-3.3, LM2587T-5.0, LM2587T-12 or LM2587T-ADJ NS Package Number T05D 26 ...

  • Page 27

    ... 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 ...