SIMPLE SWITCHER® 3.5V to 40V, 3A Low Component Count Step-Up Regulator - LM2577


SIMPLE SWITCHER® 3.5V to 40V, 3A Low Component Count Step-Up Regulator



The LM1577/LM2577 are monolithic integrated circuits that provide all of the power and control functions for step-up (boost), flyback, and forward converter switching regulators. The device is available in three different output voltage versions: 12V, 15V, and adjustable.

Requiring a minimum number of external components, these regulators are cost effective, and simple to use. Listed in this data sheet are a family of standard inductors and flyback transformers designed to work with these switching regulators.

Included on the chip is a 3.0A NPN switch and its associated protection circuitry, consisting of current and thermal limiting, and undervoltage lockout. Other features include a 52 kHz fixed-frequency oscillator that requires no external components, a soft start mode to reduce in-rush current during start-up, and current mode control for improved rejection of input voltage and output load transients.


  • Requires Few External Components
  • NPN Output Switches 3.0A, can Stand off 65V
  • Wide Input Voltage Range: 3.5V to 40V
  • Current-mode Operation for Improved Transient Response, Line Regulation, and Current Limit
  • 52 kHz Internal Oscillator
  • Soft-start Function Reduces In-rush Current During Start-up
  • Output Switch Protected by Current Limit, Under-voltage Lockout, and Thermal Shutdown

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Parametrics Compare all products in Boost Converter (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)
Special Features
Duty Cycle (Max) (%)
Operating Temperature Range (C)
Package Group
Approx. Price (US$)
LM2577 LM2585 LM2586 LM2587
3.5    4    4    4   
40    40    40    40   
1.23    1.23    1.23    1.23   
15    60    60    60   
3    4    4    6.5   
1    1    1    1   
52    85    75    85   
52    115    125    115   
10    11    11    11   
Frequency Synchronization   
95    98    98    98   
-40 to 125    -40 to 125    -40 to 125    -40 to 125   
Catalog    Catalog    Catalog    Catalog   
2.65 | 1ku    3.00 | 1ku    3.10 | 1ku    3.95 | 1ku   

Related end equipment

  • Simple Boost Regulator
  • Flyback and Forward Regulators
  • Multiple-output Regulator

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