SPRADB7 September   2023 AM2431 , AM2432 , AM2434 , AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM2732 , AM2732-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 How to Use This Application Note
    2. 1.2 Glossary
  5. 2Thermal Resistance Overview
    1. 2.1 Junction Vs. Ambient Temperature
    2. 2.2 Package Defined Thermal Resistance Characteristics
    3. 2.3 Board Defined Thermal Resistances
  6. 3Board Design Choices that Affect Thermal Performance
    1. 3.1 Thermal Vias
    2. 3.2 Board Size
    3. 3.3 Air Flow, Heat Sinking, and Enclosures
    4. 3.4 Copper Thickness
    5. 3.5 Relative Position of Heat Emitters
    6. 3.6 Layer Count
    7. 3.7 Breaks in Thermal Pathing
  7. 4Thermal Design Best Practices Review
  8. 5AM263x EVM Thermal Comparison with Data
    1. 5.1 Test Setup and Materials
    2. 5.2 Measurement Logging Software
    3. 5.3 AM263x EVM Comparison
    4. 5.4 Measurement Results
      1. 5.4.1 Lid Temperature Readings
      2. 5.4.2 Power Readings over Temperature
      3. 5.4.3 Calculated Thermal Resistance Values
      4. 5.4.4 Recorded Junction and Ambient Temperatures
      5. 5.4.5 Calculated Junction Temperature at Ambient Temperature Extremes
  9. 6Using the Thermal Model
  10. 7References

Abstract

Temperature, both internal and external to the package, can have a great influence on the characteristics of a device. The temperature of the die within the package can affect both the functionality and reliability of a device. Device packages can also become too hot and present a safety concern to users. All of these reasons and more are why the thermal properties of a printed circuit board should be heavily reviewed. Whether it is copper thickness or layer count, there are many different aspects of the PCB design that affect the thermal characteristics of the board. This document will describe many best practices and rules of thumb when it comes to thermal dissipation in PCB design. The in-depth discussion will then be put to the test through a real-world experiment that measures the junction temperature of two different AM263x evaluation modules (EVMs). The results of the experiment will be reviewed and justify how the different thermal design choices that were made in both EVMs affected the thermal performance.

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Note: While this document contains specific information and testing on the AM263x device and the AM263x evaluation modules, the thermal design principles that are described throughout the application note are applicable to all Sitara™ microcontrollers.