Parameters

Nominal value

Relative variation of thermal resistance

References

PCB copper layers

2 vs. 4 layers

54%

[8] [14]

PCB thermal vias

On-off

14%

[8] [14]

Flow velocity

2 m/s

9.4%

[15]

Underfill/C4 (between the two chips) thermal resistivity

50 mm2K/W

9.1%

[13]

Operating power

40 W

7%

[16]

TIM thermal resistivity

10 mm2K/W

5.3%

[13]

Flow angle

5%

[15]

CFD

On-off (empirical formulas)

2%

[8] [14]

Enclosure width

60 mm

2%

[16]

Distance between the heat sink and the enclosure

5.5 mm

1.1%

[15]

PCB thermal BGA

On-off

1%

[8] [14]

Substrate thermal resistivity

60 mm2K/W

0.7%

[13]

Heatsink conductivity

151 W/mK

0.34%

[15]

Underfill/C4 (between the lower chip to substrate) thermal resistivity

75 mm2K/W

negligible

[13]

Sealband thermal resistivity

600 mm2K/W

negligible

[13]