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

5.4.4 Recorded Junction and Ambient Temperatures

The temperature sweep program soaked at each ThermalAir output temperature for ten minutes during the temperature sweep. The soaking time allowed the ambient and junction temperatures to plateau. Since there are 44 steps of ten minute soaks in the incrementation from -50 to 165 ℃, then there are around 26,400 seconds per measurement sweep or around 2,640 ten second intervals. The logging script measured the ambient (Tamb), lid(Tlid) and junction (TSENSE0) temperatures every ten seconds as well, resulting in Figure 5-6.

GUID-C92FE641-1BE3-4759-9857-EABEE0E59397-low.png Figure 5-6 AM263x Control Card Temperatures with No Loading

Because the areas of the graph where the temperatures are climbing are not as important as the fully soaked temperatures, Figure 5-7 and Table 5-5 were created to more accurately represent the plateaued junction temperature readings for a given ambient temperature.

GUID-9413958D-BF0B-409B-97B7-72A5F6401EB1-low.png Figure 5-7 Junction Temperatures at Different Ambient Temperatures for AM263x Control Card and LaunchPad
Table 5-5 Measured values of Ambient and Junction Temperatures
ThermalAir Output (℃) Ambient Temp. (℃) TMDSCNCD263 Junction Temperature at TSENSE0 LP-AM263 Junction Temperature at TSENSE0
No Loading No Kapton Tape (℃) No Loading (℃) Loading Core 1 (℃) Loading Core 1/2/3 (℃) No Loading No Kapton Tape (℃) No Loading (℃) Loading Core 1 (℃) Loading Core 1/2/3 (℃)
-50 -29.6 -24 -22 -22 -22 -22 -20 -18 -20
-45 -26.6 -20 -18 -18 -18 -18 -16 -16 -16
-40 -23.3 -18 -14 -16 -14 -16 -14 -12 -12
-35 -19.9 -14 -12 -12 -12 -12 -10 -8 -8
-30 -16.4 -10 -8 -8 -8 -8 -6 -6 -6
-25 -12.9 -6 -4 -4 -4 -4 -2 -2 -2
-20 -9.3 -2 0 0 0 0 2 2 2
-15 -5.5 0 4 4 4 4 6 6 6
-10 -1.9 4 6 6 8 8 8 10 10
-5 1.7 8 10 10 10 10 12 14 14
0 5.1 12 14 14 14 14 16 16 18
5 8.4 16 18 18 18 18 20 20 22
10 11.9 18 20 22 22 22 24 24 24
15 15.4 22 24 24 24 26 28 28 28
20 19.0 26 28 28 28 30 30 32 32
25 22.7 30 32 32 32 34 34 36 36
30 26.3 34 36 36 36 38 38 40 40
35 30.6 38 40 40 40 42 44 44 44
40 34.4 42 44 44 44 46 48 48 48
45 38.1 46 48 48 48 50 52 52 52
50 41.8 50 52 52 52 54 54 56 56
55 45.4 54 56 56 56 58 58 60 60
60 48.9 58 60 60 60 62 62 64 64
65 52.4 62 64 64 64 66 66 68 68
70 55.9 66 66 66 68 70 70 70 72
75 59.4 70 70 70 72 74 74 74 76
80 62.9 74 74 74 74 76 78 78 80
85 66.2 76 78 78 78 82 82 82 84
90 69.7 80 82 82 82 84 86 86 88
95 73.0 84 86 86 86 88 90 90 92
100 76.4 88 90 90 90 92 92 94 94
105 79.8 92 94 92 94 96 96 98 98
110 83.1 96 96 96 98 100 100 102 102
115 86.4 100 100 100 100 104 104 106 106
120 89.6 102 104 104 104 108 108 108 110
125 92.9 106 108 108 108 110 112 112 114
130 96.1 110 112 112 112 114 116 116 118
135 99.3 114 116 114 116 118 120 120 122
140 102.5 118 120 118 118 122 124 124 126
145 105.6 120 124 122 122 126 128 128 128
150 108.7 124 126 126 126 128 132 132 132
155 111.9 128 130 130 130 132 136 136 136
160 115.0 132 134 132 132 136 140 140 140
165 117.9 136 138 136 138 140 144 144 146