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AC/DC & DC/DC converters (integrated FET)

LM2585

ACTIVE

4-V to 40-V, 3-A step-up wide VIN flyback regulator

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Data sheet

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LM5158 ACTIVE 3-A, 85-V, 2.2-MHz wide VIN boost, flyback, & SEPIC converter with dual random spread spectrum Newer device with higher Vout capability and higher switch current

LM2585

ACTIVE
Data sheet Order now

Product details

Rating Catalog Operating temperature range (°C) -40 to 125 Topology Boost, Flyback, Forward, SEPIC Type Converter Vin (min) (V) 4 Vin (max) (V) 40 Switching frequency (min) (kHz) 85 Switching frequency (max) (kHz) 115 Features Nonsynchronous rectification, UVLO Fixed Vout (min) (V) 1.23 Vout (max) (V) 60 Iq (typ) (µA) 11000 Duty cycle (max) (%) 98 Switch current limit (typ) (A) 4
Rating Catalog Operating temperature range (°C) -40 to 125 Topology Boost, Flyback, Forward, SEPIC Type Converter Vin (min) (V) 4 Vin (max) (V) 40 Switching frequency (min) (kHz) 85 Switching frequency (max) (kHz) 115 Features Nonsynchronous rectification, UVLO Fixed Vout (min) (V) 1.23 Vout (max) (V) 60 Iq (typ) (µA) 11000 Duty cycle (max) (%) 98 Switch current limit (typ) (A) 4
TO-220 (NDH) 5 86.0552 mm² 10.16 x 8.47 TO-263 (KTT) 5 154.8384 mm² 10.16 x 15.24
  • Requires Few External Components
  • Family of Standard Inductors and Transformers
  • NPN Output Switches 3 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 LM2585 With the WEBENCH® Power Designer
  • Requires Few External Components
  • Family of Standard Inductors and Transformers
  • NPN Output Switches 3 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 LM2585 With the WEBENCH® Power Designer

The LM2585 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 3-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 specified for the power supply system.

The LM2585 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 3-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 specified for the power supply system.
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Technical documentation

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Type Title Date
* Data sheet LM2585 4-V to 40-V, 3-A Step-Up Wide VIN Flyback Converter datasheet (Rev. G) PDF | HTML 29 May 2019
Application note Semiconductor and IC Package Thermal Metrics (Rev. D) PDF | HTML 25 Mar 2024
Application note 스트컨버터의 전력계 기본 계산 (Rev. D) PDF | HTML 21 Nov 2022
Application note Basic Calculation of a Boost Converter's Power Stage (Rev. D) PDF | HTML 28 Oct 2022
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note Inverted SEPIC Made SIMPLE 31 Jul 2015
Application note Softstart Using Constant Current Constant Voltage Approach 24 Jul 2015
Application note Working With Boost Converters 15 Jun 2015
Application note AN-2162 Simple Success With Conducted EMI From DC-DC Converters (Rev. C) 24 Apr 2013
Application note AN-1082 Adjust or Synchronize LM2586/88 Switching Frequency (Rev. B) 23 Apr 2013
Application note AN-1149 Layout Guidelines for Switching Power Supplies (Rev. C) 23 Apr 2013
Application note AN-1229 SIMPLE SWITCHER PCB Layout Guidelines (Rev. C) 23 Apr 2013
Application note AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages (Rev. B) 23 Apr 2013
Application note AN-1566 Techniques for Thermal Analysis of Switching Power Supply Designs (Rev. A) 23 Apr 2013
Application note AN-1889 How to Measure the Loop Transfer Function of Power Supplies (Rev. A) 23 Apr 2013
Application note AN-2155 Layout Tips for EMI Reduction in DC/ DC Converters (Rev. A) 23 Apr 2013
Application note Input and Output Capacitor Selection 19 Sep 2005
More literature SEM1600 Topic 4: Constructing Your Power Supply – Layout Considerations 12 Jul 2005
Application note AN-643 EMI/RFI Board Design (Rev. B) 03 May 2004
White paper It's a Buck; It's a Boost, No! It's a Switcher! (part four) 01 Sep 2003
Application note Understanding Boost Power Stages In Switchmode Power Supplies 04 Mar 1999

Design & development

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Calculation tool

FLYBUCK-FLYBACK-DESIGN-CALC — Flybuck / Flyback Calculator

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.

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
LM3017 — High Efficiency Low-Side Controller with True Shutdown LM3478 — 2.97~40V Wide Input Range Boost/SEPIC/Flyback DC-DC Controller LM3478Q-Q1 — 40-V wide VIN low-side N-channel controller for switching regulators with 10-µA shutdown current LM3481 — 2.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback LM3481-Q1 — 2.97-V to 48-V high-efficiency controller for boost, SEPIC and flyback, AEC-Q100 qualified LM3488 — 2.97V to 40V Wide Vin Low-Side N-Channel Controller for Switching Regulators LM3488Q-Q1 — 40-V wide VIN low-side N-channel controller for switching regulators with 5-µA shutdown current LM3524D — 40V, 0.2A 350KHz PWM controller LM3578A — 2-V to 40-VIN switching regulators in buck, boost, terminal, depending upon the application LM5020 — 13-100V Wide Vin, Current Mode PWM Boost, Flyback, Sepic Controller LM5022 — 6-60V Wide Vin, current mode boost, SEPIC and Flyback controller TL1451 — Dual Pulse-Width-Modulation Control Circuit TL1451A — 3.6V to 50V dual channel controller with Wide input voltage range TL1451A-EP — Enhanced Product Dual Pulse-Width-Modulation Control Circuits TL1451A-Q1 — 3.6-V to 50-V dual-channel PWM controller, AEC-Q100 qualified TL5001 — PWM Controller with wide input range, with ±5% tolerance on reference, operation –20°C to 85°C TL5001A — PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001A-Q1 — PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001M — PWM Controller with wide input range, with ±5% tolerance on reference, operation –55°C to 125°C TPS40210-Q1 — 4.5-V to 52-V wide input range current mode boost controller with 700-mV reference voltage TPS40211-Q1 — 4.5-V to 52-V wide input range current mode boost controller with 260-mV reference voltage TPS43000 — Multi-Topology (buck, boost, sepic) High Frequency DC/DC Controller TPS55010 — 2.95V To 6V Input, 2W, Isolated DC/DC Converter with Integrated FETS UC2572 — Negative output Flyback pulse width modulator
AC/DC & DC/DC converters (integrated FET)
LM25017 — 7.5-48V Wide Vin, 650mA Constant On-Time Synchronous Buck Regulator LM25018 — 7.5-48V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM25019 — 7.5-48V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM2577 — 3.5-V to 40-V, 3-A low component count step-up regulator LM2585 — 4-V to 40-V, 3-A step-up wide VIN flyback regulator LM2586 — 4-V to 40-V, 3-A step-up wide VIN flyback regulator with frequency synchronization LM2587 — 4V to 40V, 5A Step-Up Wide Vin Flyback Regulator LM2588 — 4-V to 40-V, 5-A step-up wide VIN flyback regulator with frequency synchronization LM2621 — 1.2V to 14V input voltage, 1A load current, step-up DC-DC LM2623 — 0.8V to 14V input voltage, 2A load current, step-up DC-DC LM2623-Q1 — 0.8-V to 14-V input voltage, 2-A load current, step-up DC/DC, AEC-Q100 qualified LM2735 — 520kHz/1.6MHz space efficient boost and SEPIC DC-DC regulator LM2735-Q1 — 520-kHz, 1.6-MHz space efficient boost and SEPIC DC/DC regulator, AEC-Q100 qualified LM34925 — 7.5-100V Wide Vin, 100mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34926 — 7.5-100V Wide Vin, 300mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34927 — 7.5-100V Wide Vin, 600mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM5000 — 3.1-40V Wide Vin, 2A Current Mode Non-Synchronous Boost Regulator LM5001 — 3.1-75V Wide Vin, 1A Current Mode Non-Synchronous Switch Mode Regulator LM5001-Q1 — 3.1-V to 75-V wide VIN, 1-A current mode non-synchronous switch mode regulator LM5002 — 3.1-75V Wide Vin, 0.5A Current Mode Boost, Flyback, Sepic Converter LM5015 — 4.25-75V, Monolithic Two-Switch Forward DC-DC Regulator LM5017 — 7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator LM5018 — 7.5-100V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM5019 — 7.5-100V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM5160 — LM5160 wide input 65V, 2A synchronous buck/Fly-Buck™ converter LM5160-Q1 — Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5160A — LM5160A Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5161 — Wide Input 4.5-V to 100-V, 1-A Synchronous Buck / Fly-Buck Converter LM78S40 — 1.5A Adjustable Step Up, Step Down or Inverting Regulator TPS55340 — 5-A, 40-V, wide VIN boost, flyback, & SEPIC converter TPS55340-EP — Enhanced integrated, 5-A, 40-V wide input range boost/SEPIC/flyback DC/DC regulator TPS55340-Q1 — Integrated, 5-A 40-V wide input range boost/SEPIC/flyback DC/DC regulator, AEC-Q100 qualified TPS61175 — 3-A ,40V High Voltage Boost Converter with Soft-start and Programmable Switching Frequency TPS61175-Q1 — 3-A, 40-V high voltage boost converter with soft-start and programmable switching frequency
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