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LM2577

ACTIVE

3.5-V to 40-V, 3-A low component count step-up regulator

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Data sheet

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LM5157 ACTIVE 6A/4A, 50-V, 2.2-MHz wide VIN boost, flyback, & SEPIC converter with dual random spread spectrum Integrated, 6-A 50-V wide-input range.

LM2577

ACTIVE
Data sheet Order now

Product details

Rating Catalog Topology Boost, Flyback, Forward, SEPIC Vin (max) (V) 40 Vin (min) (V) 3.5 Vout (max) (V) 60 Vout (min) (V) 1.23 Switch current limit (typ) (A) 3 Features Nonsynchronous rectification, UVLO fixed Operating temperature range (°C) -40 to 125 Iq (typ) (A) 0.01 Duty cycle (max) (%) 95
Rating Catalog Topology Boost, Flyback, Forward, SEPIC Vin (max) (V) 40 Vin (min) (V) 3.5 Vout (max) (V) 60 Vout (min) (V) 1.23 Switch current limit (typ) (A) 3 Features Nonsynchronous rectification, UVLO fixed Operating temperature range (°C) -40 to 125 Iq (typ) (A) 0.01 Duty cycle (max) (%) 95
TO-263 (KTT) 5 154.8384 mm² (10.16 mm × 15.24 mm) TO-220 (NDH) 5 86.0552 mm² (10.16 mm × 8.47 mm) TO-220 (KC) 5 45.212 mm² (10.16 mm × 4.45 mm)
  • 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

All trademarks are the property of their respective owners.
  • 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

All trademarks are the property of their respective owners.

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.

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.
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Technical documentation

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Top documentation Type Title Format options Date
* Data sheet LM1577/LM2577 SIMPLE SWITCHER Step-Up Voltage Regulator datasheet (Rev. D) Apr 3, 2013
Application note Semiconductor and IC Package Thermal Metrics (Rev. D) PDF | HTML Mar 25, 2024
Application note Basic Calculation of a Boost Converter's Power Stage (Rev. D) PDF | HTML Oct 28, 2022
Application note Switching regulator fundamentals (Rev. C) PDF | HTML Feb 5, 2019
Application note Working With Boost Converters Jun 15, 2015
Application note AN-2162 Simple Success With Conducted EMI From DC-DC Converters (Rev. C) Apr 24, 2013
Application note AN-777 LM2577 Three Output, Isolated Flyback Regulator (Rev. B) Apr 23, 2013
Application note AN-1566 Techniques for Thermal Analysis of Switching Power Supply Designs (Rev. A) Apr 23, 2013
Application note AN-2155 Layout Tips for EMI Reduction in DC/ DC Converters (Rev. A) Apr 23, 2013
Application note AN-1229 SIMPLE SWITCHER PCB Layout Guidelines (Rev. C) Apr 23, 2013
Application note AN-1149 Layout Guidelines for Switching Power Supplies (Rev. C) Apr 23, 2013
Application note AN-1889 How to Measure the Loop Transfer Function of Power Supplies (Rev. A) Apr 23, 2013
Application note AN-776 20-W SIMPLE SWITCHER Forward Converter (Rev. A) Apr 23, 2013
Application note AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages (Rev. B) Apr 23, 2013
Application note Negative Buck Switching Regulator (using LM258x) Mar 21, 2007
Application note Input and Output Capacitor Selection Sep 19, 2005
More literature SEM1600 Topic 4: Constructing Your Power Supply – Layout Considerations Jul 12, 2005
Application note AN-643 EMI/RFI Board Design (Rev. B) May 3, 2004
Application note Understanding Boost Power Stages In Switchmode Power Supplies Mar 4, 1999

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TO-263 (KTT) 5 Ultra Librarian
TO-220 (NDH) 5 Ultra Librarian
TO-220 (KC) 5 Ultra Librarian
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