SNVA951 November   2020 LM61460-Q1 , LM63615-Q1 , LM63625-Q1 , LM63635-Q1 , LMR33620-Q1 , LMR33630-Q1

 

  1.   Trademarks
  2. Introduction
  3. The Goal of Thermal Management
  4. Junction Temperature Calculation
    1. 3.1 Regulator Junction Temperature (TJ)
    2. 3.2 Ambient Temperature (TA)
    3. 3.3 Power Dissipation (PD)
    4. 3.4 Thermal Resistance (θJA)
      1. 3.4.1 Thermal Metrics
  5. Package Type
  6. PCB Copper Heat Sink
  7. PCB Layout Tips
  8. Estimating and Measuring θJA
    1. 7.1 Simple Guideline
    2. 7.2 Data Sheet Curves
    3. 7.3 Simplified Heat Flow Spreadsheet
    4. 7.4 Online Database
    5. 7.5 Thermal Simulators
  9. Measuring Thermal Performance
    1. 8.1 Thermal Camera
    2. 8.2 Thermocouple
    3. 8.3 Internal Diode
  10. Thermal Design Example
  11. 10Conclusion
  12. 11References

Conclusion

By using the thermal metrics found in the converter data sheet and a few simple equations, the thermal performance of a given application can usually be estimated well enough for engineering purposes. The considerations given here can provide sufficient information about the thermal performance for comparison purposes or may even provide a good estimate for a final design. Of course, as with any engineering endeavor, testing of a prototype application will provide the best possible measure of performance in the final product; however using the guidance in this paper, your first design is more likely to be your final design.