How should the heat dissipation pad area of a high-current common-mode inductor be calculated? ​

The heat dissipation pad area of high-current common-mode inductors needs to be calculated in conjunction with power consumption, temperature rise limits, and PCB thermal conductivity characteristics. The core formula is:

The heat dissipation area S ≈ power consumption P / (allowable temperature rise ΔT × thermal conductivity K).

Here, power consumption P mainly includes winding copper loss (I²R, where I is the rated current and R is the winding resistance) and core loss (related to frequency and magnetic flux density). The allowable temperature rise ΔT (usually taken as 40-60℃, determined according to application scenarios such as industrial grade and automotive grade) is related to the PCB material (e.g., FR4 has a thermal conductivity of about 0.2-0.3 W/(m·K)). In actual design, it is necessary to refer to the thermal resistance parameters of the inductor datasheet and optimize through thermal simulation (such as ANSYS Icepak). It is generally recommended that the area of the heat dissipation pad be no less than 1.5-2 times the projected area of the inductor bottom.