LM2577

ACTIVE

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

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Product details

Parameters

Vin (Min) (V) 3.5 Vin (Max) (V) 40 Vout (Min) (V) 1.23 Vout (Max) (V) 15 Switch current limit (Typ) (A) 3 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 52 Switching frequency (Max) (kHz) 52 Iq (Typ) (mA) 10 Duty cycle (Max) (%) 95 Operating temperature range (C) -40 to 125 Rating Catalog open-in-new Find other Boost converters (integrated switch)

Package | Pins | Size

TO-220 (KC) 5 86 mm² 10.2 x 8.7 TO-220 (NDH) 5 86 mm² 10.16 x 8.47 TO-263 (KTT) 5 155 mm² 10.16 x 15.24 open-in-new Find other Boost converters (integrated switch)

Features

  • 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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Description

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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Type Title Date
* Datasheet LM1577/LM2577 SIMPLE SWITCHER Step-Up Voltage Regulator datasheet (Rev. D) Apr. 03, 2013
Application notes Switching regulator fundamentals (Rev. C) Feb. 05, 2019
Application notes Semiconductor and IC Package Thermal Metrics (Rev. C) Apr. 19, 2016
Application notes Working With Boost Converters Jun. 15, 2015
Application notes Basic Calculation of a Boost Converter's Power Stage (Rev. C) Jan. 08, 2014
Application notes AN-2162 Simple Success With Conducted EMI From DC-DC Converters (Rev. C) Apr. 24, 2013
Application notes AN-1149 Layout Guidelines for Switching Power Supplies (Rev. C) Apr. 23, 2013
Application notes AN-1229 SIMPLE SWITCHER PCB Layout Guidelines (Rev. C) Apr. 23, 2013
Application notes AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages (Rev. B) Apr. 23, 2013
Application notes AN-1566 Techniques for Thermal Analysis of Switching Power Supply Designs (Rev. A) Apr. 23, 2013
Application notes AN-1889 How to Measure the Loop Transfer Function of Power Supplies (Rev. A) Apr. 23, 2013
Application notes AN-2155 Layout Tips for EMI Reduction in DC/ DC Converters (Rev. A) Apr. 23, 2013
Application notes AN-776 20-W SIMPLE SWITCHER Forward Converter (Rev. A) Apr. 23, 2013
Application notes AN-777 LM2577 Three Output, Isolated Flyback Regulator (Rev. B) Apr. 23, 2013
Application notes Negative Buck Switching Regulator (using LM258x) Mar. 21, 2007
Application notes Input and Output Capacitor Selection Sep. 19, 2005
More literature SEM1600 Topic 4: Constructing Your Power Supply – Layout Considerations Jul. 12, 2005
Application notes AN-643 EMI/RFI Board Design (Rev. B) May 03, 2004
Application notes Understanding Boost Power Stages In Switchmode Power Supplies Mar. 04, 1999

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Design tools & simulation

CALCULATION TOOLS Download
Fly-Buck and Flyback Topology Selector
FLYBUCK-FLYBACK-DESIGN-CALC This tool helps a power supply engineer to select the right isolated DC-DC topology based on the specifications. Depending on the topology chosen, the calculator also recommends the right IC for the design.
Features
  • Features isolated topologies like Fly-Buck™, Fly-Buck-Boost, DCM and CCM Flyback
  • Capability to design up to 6 isolated outputs
  • Recommends ICs for desired application design
  • Incorporates loop compensation in designs
  • Compares efficiency, external component count and transformer currents for every topology (...)
DESIGN TOOLS Download
Switchers Made Simple
SWITCHERSMADESIMPLE-SW Note: The Switchers Made Simple design computations have been incorporated into Texas Instruments' award winning WEBENCH Power Designer Online Design Tool. Please use TI's WEBENCH Power Designer online tools for new designs. The WEBENCH Design Tool also includes:
  • Visual design optimization for (...)

CAD/CAE symbols

Package Pins Download
DDPAK/TO-263 (KTT) 5 View options
TO-220 (KC) 5 View options
TO-220 (NDH) 5 View options

Ordering & quality

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