SPRADB7 September   2023 AM2431 , AM2432 , AM2434 , AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM263P4-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

5.4.2 Power Readings over Temperature

The Operating Power was recorded during the measurements by polling the two INA228 power monitors for the 1.2 V and 3.3 V supply rail operating power. These two values were added together and then 125 mV was added to account for the VDDA supply rail operating power.

The operating power was recorded in four different configurations. The first three included Kapton tape on the package for lid temperature measurements. These three configurations included when only the logging script was run on R5_0 (CC_noLoad), the logging script run on R5_0 and R5_1 run at full load (CC_Load1), and the logging script run on R5_0 and R5_1/2/3 run at full load (CC_Load123). The final configuration for power measurement was when no Kapton tape was on top of the package, resulting in a noticeably decreased operating power due to the decreased thermal resistance between case temperature and ambient temperature or RΘCA.

Table 5-2 Power Measurements at Temperature Extremes for the AM263x Control Card
ThermalAir Airstream Output Ambient Temperature Reading CC_noLoadNoTape Power CC_noLoad Power CC_Load1 Power CC_Load123 Power
-50℃ -29.4 ℃ 1.21 W 1.30 W 1.32 W 1.36 W
165℃ 118.6 ℃ 1.60 W 1.71 W 1.73 W 1.77 W
GUID-3D8D7944-8CAC-4809-974C-D35F3C5D3D2C-low.png Figure 5-5 AM263x Control Card Device Operating Power Across Ambient Temperature Sweep