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

6.6 Typical Characteristics

All curves taken at VIN = 5 V with configuration in typical application circuits shown in Application and Implementation. TJ = 25°C, unless otherwise specified.
LM26420 30069682.png
Figure 1. Efficiency vs Load, X Option
LM26420 LM26420_Efficiency_Up_to_93_Percent.png
Figure 3. Efficiency vs Load, X Option
LM26420 30069690.png
Figure 5. Efficiency vs Load, X Option
LM26420 30069688.png
Figure 7. Efficiency vs Load, X Option
LM26420 30069641.png
Figure 9. Efficiency vs Load, X Option
LM26420 30069643_nvs579.gif
VIN = 5 V VOUT = 1.8 V
Figure 11. Load Regulation (All Options)
LM26420 30069627_nvs579.gif
VOUT = 1.8 V IOUT = 1000 mA
Figure 13. Line Regulation, X Option
LM26420 30069647.png
Figure 15. Oscillator Frequency vs Temperature,, X Option
LM26420 30069649_nvs579.gif
Figure 17. RDSON Top Vs Temperature (WQFN-16 Package)
LM26420 30069691_nvs579.gif
Figure 19. RDSON Top Vs Temperature (TSSOP-20 Package)
LM26420 30069654_nvs579.gif
Figure 21. IQ (Quiescent Current Switching), X Option
LM26420 30069659.png
Figure 23. VFB vs Temperature
LM26420 30069680_nvs579.gif
Figure 25. Reverse Current Limit vs Temperature
LM26420 30069683.png
Figure 2. Efficiency Vs Load, Y Option
LM26420 30069685.png
Figure 4. Efficiency vs Load, Y Option
LM26420 30069687.png
Figure 6. Efficiency vs Load, Y Option
LM26420 30069689.png
Figure 8. Efficiency vs Load, Y Option
LM26420 30069642.png
Figure 10. Efficiency vs Load, Y Option
LM26420 30069645_nvs579.gif
VIN = 3 V VOUT = 1.8 V
Figure 12. Load Regulation (All Options)
LM26420 30069646_nvs579.gif
VOUT = 1.8 V IOUT = 1000 mA
Figure 14. Line Regulation - Y Option
LM26420 30069648.png
Figure 16. Oscillator Frequency vs Temperature, Y Option
LM26420 30069650_nvs579.gif
Figure 18. RDSON Bottom Vs Temperature
(WQFN-16 Package)
LM26420 30069692x_nvs579.gif
Figure 20. RDSON Bottom vs Temperature
(TSSOP-20 Package)
LM26420 30069655_nvs579.gif
Figure 22. IQ (Quiescent Current Switching), Y Option
LM26420 30069653_nvs579.gif
VIN = 5 V and 3.3 V
Figure 24. Current Limit vs Temperature
LM26420 30069698.png
Figure 26. Short Circuit Waveforms