SNVS579L February   2009  – May 2018 LM26420

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      LM26420 Dual Buck DC/DC Converter
      2.      LM26420 Efficiency (Up to 93%)
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: 16-Pin WQFN
    2.     Pin Functions 20-Pin HTSSOP
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings (LM26420X/Y)
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics Per Buck
    6. 6.6 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 Soft Start
      2. 7.3.2 Power Good
      3. 7.3.3 Precision Enable
    4. 7.4 Device Functional Modes
      1. 7.4.1 Output Overvoltage Protection
      2. 7.4.2 Undervoltage Lockout
      3. 7.4.3 Current Limit
      4. 7.4.4 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Programming Output Voltage
      2. 8.1.2 VINC Filtering Components
      3. 8.1.3 Using Precision Enable and Power Good
      4. 8.1.4 Overcurrent Protection
    2. 8.2 Typical Applications
      1. 8.2.1 LM26420X 2.2-MHz, 0.8-V Typical High-Efficiency Application Circuit
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2 Inductor Selection
          3. 8.2.1.2.3 Input Capacitor Selection
          4. 8.2.1.2.4 Output Capacitor
          5. 8.2.1.2.5 Calculating Efficiency and Junction Temperature
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM26420X 2.2-MHz, 1.8-V Typical High-Efficiency Application Circuit
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LM26420X 2.2-MHz, 2.5-V Typical High-Efficiency Application Circuit
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
      4. 8.2.4 LM26420Y 550 kHz, 0.8-V Typical High-Efficiency Application Circuit
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
      5. 8.2.5 LM26420Y 550-kHz, 1.8-V Typical High-Efficiency Application Circuit
        1. 8.2.5.1 Design Requirements
        2. 8.2.5.2 Detailed Design Procedure
        3. 8.2.5.3 Application Curves
      6. 8.2.6 LM26420Y 550-kHz, 2.5-V Typical High-Efficiency Application Circuit
        1. 8.2.6.1 Design Requirements
        2. 8.2.6.2 Detailed Design Procedure
        3. 8.2.6.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
      1. 10.3.1 Method 1: Silicon Junction Temperature Determination
      2. 10.3.2 Thermal Shutdown Temperature Determination
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.4.2 Undervoltage Lockout

Undervoltage lockout (UVLO) prevents the LM26420 from operating until the input voltage exceeds 2.628 V (typical). The UVLO threshold has approximately 330 mV of hysteresis, so the device operates until VIN drops below 2.3 V (typical). Hysteresis prevents the part from turning off during power up if VIN is non-monotonic.