Tool/software:
I used the following formula, which shows the temperature rise and pattern cross-sectional area of MIL-STD-275E, as a reference.
RefURL : keisan.casio.jp/.../1663912785
A: Cross-sectional area [mm^2] .... Copper foil thickness: 18um. Minimum pattern width: 0.3mm
k: Coefficient by wiring layer. 0.024 for inner layer. 0.048 for outer layer. ...Outer layer this time
ΔT: Temperature rise [℃] ... I would like to keep it to about 20℃
I: Current [A] ... 3A this time
The point with the highest current density is the 0.3mm pad width of the SW pin of SOT-563.
According to the calculation, if 3A flows with the minimum pattern width of 0.3mm (SW pin), the pattern temperature will rise by nearly 300℃.
The TPS564247 has a maximum of 4A, so I think the above calculation is incorrect.
How should I calculate the temperature rise of the minimum pattern width SW pin pad (point indicated by the black arrow below) for this IC?
My specifications are shown below.
Input voltage: 12V
Output voltage: 5V
Maximum current: 3.1A
Copper foil thickness: 18um
Board diagram below. The IC near C1 is the TPS564247
