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LM2587
SNVS115E – APRIL 2000 – REVISED JUNE 2019
LM2587 4-V To 40-V, 5-A Step-Up Wide VIN Flyback Regulator
1 Features
•1 Requires Few External Components
• Family of Standard Inductors and Transformers
• NPN Output Switches 5 A, Can Stand Off 65 V
• Wide Input Voltage Range: 4 V to 40 V
• Current-mode Operation for Improved Transient
Response, Line Regulation, and Current Limit
• 100-kHz Switching Frequency
• Internal Soft-Start Function Reduces In-rush
Current During Start-up
• Output Transistor Protected by Current Limit,
Undervoltage Lockout, and Thermal Shutdown
• System Output Voltage Tolerance of ±4%
Maximum Over Line and Load Conditions
• Create a Custom Design Using the LM2587 With
the WEBENCH® Power Designer
2 Typical Applications
• Flyback Regulator
• Multiple-Output Regulator
• Simple Boost Regulator
• Forward Converter
3 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: 3.3 V, 5 V, 12 V, and adjustable.
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 regulators. Also listed
are selector guides for diodes and capacitors and a
family of standard inductors and flyback transformers
designed to work with these switching regulators.
The power switch is a 5-A NPN device that can
stand-off 65 V. 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 limiting. An output voltage tolerance of ±4%,
within specified input voltages and output load
conditions, is ensured for the power supply system.
Device Information(1)
PART NUMBER PACKAGE
BODY SIZE (NOM)
LM2587
DDPAK/ TO-263 (5) 10.16 mm × 8.42 mm
TO-220 (5)
14.986 mm × 10.16 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Flyback Regulator
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
