LM2587 4V to 40V, 5A Step-Up Wide Vin Flyback Regulator | TI.com


4V to 40V, 5A Step-Up Wide Vin Flyback Regulator

4V to 40V, 5A Step-Up Wide Vin Flyback Regulator - LM2587


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 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 5.0A 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 limiting. An output voltage tolerance of ±4%, within specified input voltages and output load conditions, is ensured for the power supply system.


  • Requires Few External Components
  • Family of Standard Inductors and Transformers
  • NPN Output Switches 5.0A, can Stand Off 65V
  • Wide Input Voltage Range: 4V to 40V
  • 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, Under Voltage Lockout, and Thermal Shutdown
  • System Output Voltage Tolerance of ±4% Max Over Line and Load Conditions

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Parametrics Compare all products in Boost converters (integrated switch)

Vin (Min) (V)
Vin (Max) (V)
Vout (Min) (V)
Vout (Max) (V)
Switch Current Limit (Typ) (A)
Regulated outputs (#)
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Duty cycle (Max) (%)
Operating temperature range (C)
Package Group
LM2587 LM2585 LM2586 LM5000 TPS55340
4     4     4     3.1     2.9    
40     40     40     40     32    
1.23     1.23     1.23     1.259     3    
60     60     60     75     38    
6.5     4     4     2     6.6    
1     1     1     1     1    
85     85     75     300     100    
115     115     125     1300     1200    
11     11     11     2.1     0.5    
Frequency Synchronization    
Enable     Enable
Frequency Synchronization
Light Load Efficiency    
98     98     98     90     90    
-40 to 125     -40 to 125     -40 to 125     -40 to 125     -40 to 150    
Converter     Converter     Converter     Converter     Converter    
Catalog     Catalog     Catalog     Catalog     Catalog    
DDPAK/TO-263 | 5
TO-220 | 5    
DDPAK/TO-263 | 5
TO-220 | 5    
DDPAK/TO-263 | 7
TO-220 | 7    
TSSOP | 16
WSON | 16    
WQFN | 16    

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WEBENCH® Designer LM2587

  Min   Max Range
Vin  V 4.0 to 40.0V
Vout  V 1.23 to 300V
Iout  A ≤ 5A
Ambient Temp  °C -40 to 125°C