SNVSA38 November   2014 LM3281

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 System Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Small Solution Size
      2. 7.3.2  Automatic Analog Bypass with Low Dropout
      3. 7.3.3  Low IQ
      4. 7.3.4  Forced PWM Operation
      5. 7.3.5  High Maximum Current
      6. 7.3.6  High-Capacitance Load and Line Transient Performance
      7. 7.3.7  Soft Start
      8. 7.3.8  Thermal Overload Protection
      9. 7.3.9  Current Limit
      10. 7.3.10 Power-On Reset
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 Forced PWM (FPWM) Mode
      3. 7.4.3 Analog Bypass Mode
      4. 7.4.4 ECO (Economy) Mode
      5. 7.4.5 Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Suggested Passive Components
          1. 8.2.1.1.1 LM3281 Inductor Selection
          2. 8.2.1.1.2 Total Effective Output Capacitance (COUT + CLOAD1 + CLOAD2)
          3. 8.2.1.1.3 LM3281 Capacitor (CIN and COUT) Selection
          4. 8.2.1.1.4 Recommended Load Bypass Capacitors (CLOAD1 and CLOAD2)
          5. 8.2.1.1.5 Alternate Output Capacitor Configuration
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 COUT-to-CLOAD Inductance
      2. 10.1.2 LM3281-to-CIN Inductance
    2. 10.2 Layout Example
    3. 10.3 DSBGA Package Assembly And Use
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    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

9 Power Supply Recommendations

The LM3281 device is designed to operate from a supply voltage range between 3 V and 5.5 V. This input supply should be well regulated. If the input supply is located more than a few inches from the LM3281 converter, additional bulk capacitance may be required in addition to the ceramic bypass capacitors. An electrolytic or tantalum capacitor with a value of 47 μF is a typical choice.