SNVSB35B May   2018  – June 2020

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      LM26420 Dual Buck DC/DC Converter
      2.      LM26420 Efficiency (Up to 93%)
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions: 16-Pin WQFN
    2.     Pin Functions 20-Pin HTSSOP
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics Per Buck
    6. 6.6 Typical Characteristics
  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. 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 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 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 LM26420-Q12.2-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
  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 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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-Q1 30069682.png
Figure 1. Efficiency vs Load
LM26420-Q1 30069690.png
Figure 3. Efficiency vs Load
LM26420-Q1 30069641.png
Figure 5. Efficiency vs Load
LM26420-Q1 30069645_nvs579.gif
VIN = 3 V VOUT = 1.8 V
Figure 7. Load Regulation
LM26420-Q1 30069647.png
Figure 9. Oscillator Frequency vs Temperature,
LM26420-Q1 30069650_nvs579.gif
Figure 11. RDSON Bottom Vs Temperature
(WQFN-16 Package)
LM26420-Q1 30069692x_nvs579.gif
Figure 13. RDSON Bottom vs Temperature
(TSSOP-20 Package)
LM26420-Q1 30069659.png
Figure 15. VFB vs Temperature
LM26420-Q1 30069680_nvs579.gif
Figure 17. Reverse Current Limit vs Temperature
LM26420-Q1 C002_SNVS579.png
Figure 19. IQ (Quiescent Current) vs Temperature
(Q0 Grade)
LM26420-Q1 C005_SNVS579.png
Figure 21. Current Limit vs Temperature (Q0 Grade)
LM26420-Q1 C007_SNVS579.png
Figure 23. RDSON Top vs Temperature (Q0 Grade)
LM26420-Q1 C009_SNVS579.png
Figure 25. Oscillator Frequency vs Temperature (Q0 Grade)
LM26420-Q1 LM26420_Efficiency_Up_to_93_Percent.png
Figure 2. Efficiency vs Load
LM26420-Q1 30069688.png
Figure 4. Efficiency vs Load
LM26420-Q1 30069643_nvs579.gif
VIN = 5 V VOUT = 1.8 V
Figure 6. Load Regulation
LM26420-Q1 30069627_nvs579.gif
VOUT = 1.8 V IOUT = 1000 mA
Figure 8. Line Regulation
LM26420-Q1 30069649_nvs579.gif
Figure 10. RDSON Top Vs Temperature (WQFN-16 Package)
LM26420-Q1 30069691_nvs579.gif
Figure 12. RDSON Top Vs Temperature (TSSOP-20 Package)
LM26420-Q1 30069654_nvs579.gif
Figure 14. IQ (Quiescent Current Switching)
LM26420-Q1 30069653_nvs579.gif
VIN = 5 V and 3.3 V
Figure 16. Current Limit vs Temperature
LM26420-Q1 30069698.png
Figure 18. Short Circuit Waveforms
LM26420-Q1 C004_SNVS579.png
Figure 20. VFB vs Temperature (Q0 Grade)
LM26420-Q1 C006_SNVS579.png
Figure 22. Reverse Current Limit vs Temperature (Q0 Grade)
LM26420-Q1 C008_SNVS579.png
Figure 24. RDSON Bottom vs Temperature (Q0 Grade)