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  5. LT3581

Data Sheet
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User Guides
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Overview

Features and Benefits

  • 3.3A, 42V Combined Power Switch
  • Master/Slave (1.9A/1.4A) Switch Design
  • Output Short Circuit Protection
  • Wide Input Range: 2.5V to 22V Operating, 40V Maximum Transient
  • Switching Frequency Up to 2.5MHz
  • Easily Configurable as a Boost, SEPIC, Inverting or Flyback Converter
  • User Configurable Undervoltage Lockout
  • Low VCESAT Switch: 250mV at 2.75A (Typical)
  • Can be Synchronized to External Clock
  • Can Be Synchronized to other Switching Regulators
  • High Gain SHDN Pin Accepts Slowly Varying Input Signals
  • 14-Pin 4mm × 3mm DFN and 16-Lead MSE Packages

Product Details

The LT3581 is a PWM DC/DC converter with built-in fault protection features to aid in protecting against output shorts, input/output overvoltages, and overtemperature conditions. The part consists of a 42V master switch, and a 42V slave switch that can be tied together for a total current limit of 3.3A.

The LT3581 is ideal for many local power supply designs. It can be easily configured in Boost, SEPIC, Inverting or Flyback configurations, and is capable of generating 12V at 830mA, or –12V at 625mA from a 5V input. In addition, the LT3581’s slave switch allows the part to be configured in high voltage, high power charge pump topologies that are very efficient and require fewer components than traditional circuits.

The LT3581’s switching frequency range can be set between 200kHz and 2.5MHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to ground, or it may be synchronized to an external clock. A buffered version of the clock signal is driven out of the CLKOUT pin, and may be used to synchronize other compatible switching regulator ICs to the LT3581.

The LT3581 also features innovative SHDN pin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. Additional features such as frequency foldback and soft-start are integrated. The LT3581 is available in 14-Pin 4mm × 3mm DFN and 16-Lead MSE packages.

Applications

  • Local Power Supply
  • Vacuum Fluorescent Display (VFD) Bias Supplies
  • TFT-LCD Bias Supplies
  • Automotive Engine Control Unit (ECU) Power

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Evaluation Kits (2)

Documentation & Resources

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  • Data Sheets (1)
  • Reliability Data (1)
  • Application Notes (1)
  • User Guides (1)
  • Videos (1)
  • Press Releases (1)
  • Technical Articles (3)
    • Document Type

    Tools & Simulations

    LTspice

    LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

    To launch ready-to-run LTspice demonstration circuits for this part:

    Step 1: Download and install LTspice on your computer.

    Step 2: Click on the link in the section below to download a demonstration circuit.

    Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

    LTspice

    LTspice Simulations

    LT3581 Demo Circuit - 3.3A, Boost/Inverting DC/DC Converter with Fault Protection (5V to 12V @ 900mA)

    Models for the following parts are available in LTspice:

    LT3581

    Product Recommendations

    LT3581 Companion Parts

    Recommended Related Parts

    Design Resources

    ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

    Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
    LT3581EDE#PBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581EDE#TRPBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581EMSE#PBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
    LT3581EMSE#TRPBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
    LT3581HDE#PBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581HDE#TRPBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581IDE#PBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581IDE#TRPBF Material Declaration Reliability Data 14-Lead DFN (4mm x 3mm w/ EP)
    LT3581IMSE#PBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
    LT3581IMSE#TRPBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
    Wafer Fabrication Data R530 Reliability Data

    PCN-PDN Information

    Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

    Select Model for PCN Information
    • LT3581EDE#PBF Production
    • LT3581EDE#TRPBF Production
    • LT3581EMSE#PBF Production
    • LT3581EMSE#TRPBF Production
    • LT3581HDE#PBF Production
    • LT3581HDE#TRPBF Production
    • LT3581IDE#PBF Production
    • LT3581IDE#TRPBF Production
    • LT3581IMSE#PBF Production
    • LT3581IMSE#TRPBF Production

    Support & Discussions

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