SNVS582O September   2008  – August 2015 LM22677 , LM22677-Q1

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 ESD Ratings: LM22677
    3. 6.3 ESD Ratings: LM22677-Q1
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Thermal Information
    6. 6.6 Electrical 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 Precision Enable and UVLO
      2. 7.3.2 Soft-Start
      3. 7.3.3 Switching Frequency Adjustment and Synchronization
      4. 7.3.4 Self Synchronization
      5. 7.3.5 Boot-Strap Supply
      6. 7.3.6 Internal Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Current Limit
      2. 7.4.2 Thermal Protection
      3. 7.4.3 Duty-Cycle Limits
  8. 8 Applications and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Output Voltage Divider Selection
      2. 8.1.2 Power Diode
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 External Components
        2. 8.2.2.2 Inductor
        3. 8.2.2.3 Input Capacitor
        4. 8.2.2.4 Output Capacitor
        5. 8.2.2.5 Boot-Strap Capacitor
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 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

9 Power Supply Recommendations

The LM22677 is designed to operate from an input voltage supply range between 4.5 V and 42 V. This input supply should be able to withstand the maximum input current and maintain a voltage above 4.5 V. The resistance of the input supply rail should be low enough that an input current transient does not cause a high enough drop at the LM22677 supply voltage that can cause a false UVLO fault triggering and system reset.

If the input supply is located more than a few inches from the LM22677 additional bulk capacitance may be required in addition to the ceramic bypass capacitors. The amount of bulk capacitance is not critical, but a 47 µF or 100 µF electrolytic capacitor is a typical choice.