SNVS346F November   2007  – November 2014 LM3481 , LM3481-Q1


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling Ratings: LM3481
    3. 6.3 Handling Ratings: LM3481-Q1
    4. 6.4 Recommended Operating Ratings
    5. 6.5 Thermal Information
    6. 6.6 Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Overvoltage Protection
      2. 7.3.2 Bias Voltage
      3. 7.3.3 Slope Compensation Ramp
      4. 7.3.4 Frequency Adjust, Synchronization, and Shutdown
      5. 7.3.5 Undervoltage Lockout (UVLO) Pin
      6. 7.3.6 Short-Circuit Protection
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Boost Converter
        1. Design Requirements
        2. Detailed Design Procedure
          1.  Custom Design with WEBENCH Tools
          2.  Power Inductor Selection
          3.  Programming the Output Voltage and Output Current
          4.  Current Limit With Additional Slope Compensation
          5.  Power Diode Selection
          6.  Power MOSFET Selection
          7.  Input Capacitor Selection
          8.  Output Capacitor Selection
          9.  Driver Supply Capacitor Selection
          10. Compensation
        3. Application Curve
      2. 8.2.2 Typical SEPIC Converter
        1. Design Requirements
        2. Detailed Design Procedure
          1. Power MOSFET Selection
          2. Power Diode Selection
          3. Selection of Inductors L1 and L2
          4. Sense Resistor Selection
          5. SEPIC Capacitor Selection
          6. Input Capacitor Selection
          7. Output Capacitor Selection
        3. Application Curve
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Custom Design with WEBENCH Tools
      2. 11.1.2 Receiving Notification of Documentation Updates
      3. 11.1.3 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

11 Device and Documentation Support

11.1 Documentation Support

11.1.1 Custom Design with WEBENCH Tools

Click here to create a custom design using the LM3481 device with the WEBENCH® Power Designer.

  1. Start by entering your VIN, VOUT and IOUT requirements.
  2. Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments.
  3. WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability.
  4. In most cases, you will also be able to:
    • Run electrical simulations to see important waveforms and circuit performance,
    • Run thermal simulations to understand the thermal performance of your board,
    • Export your customized schematic and layout into popular CAD formats,
    • Print PDF reports for the design, and share your design with colleagues.
  5. Get more information about WEBENCH tools at

11.1.2 Receiving Notification of Documentation Updates

To receive notification of documentation updates, navigate to the device product folder on In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document.

11.1.3 Related Documentation

  • AN-1286 Compensation for the LM3478 Boost Controller (SNVA067)
  • AN-2094 LM3481 SEPIC Evaluation Board (SNVA461)
  • AN-1229 SIMPLE SWITCHER® PCB Layout Guidelines (SNVA054)
  • SNVU111 330mW AC or DC Tiny Flyback Converter Power Supply (SNVU111)

11.2 Related Links

The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy.

Table 1. Related Links

LM3481 Click here Click here Click here Click here Click here
LM3481-Q1 Click here Click here Click here Click here Click here

11.3 Trademarks

WEBENCH is a registered trademark of Texas Instruments.

11.4 Electrostatic Discharge Caution


These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.

11.5 Glossary

SLYZ022TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.