Online calculator for the thermal properties in the plate direction for multi-layer glass-epoxy PCBs.

For calculations perpendicular to the plate direction see: Thermal Resistance from Pads to inner Layers.

Related links
Thermal design for electronics
Thermal online tools
Unit conversion
Comments

General

The thermal conductivity is of importance for temperature calculations on PCBs. The accuracy of this value is however not super critical. It is in most cases sufficient to know it within +/- 20%, see: The Cooling Efficiency Concept, part 2.

The procedure is based on a simple proportionally method. The values shown within parenthesis are the results of the preceding calculation.


Inputs

Count. Is the number of layers.

Thickness. Is the thickness of the layers.

Fill factor. This factor is used handle the fact that no copper layers is intact. It is not a measure on the physical copper content but rather a reduction factor. Default values are 20% for signal layers and 80% for power and ground layers.


Material data used

Copper:
Cp = 393 [J/kgK]
Cond = 390 [W/mK]
Density = 8930 [kg/m3]

FR4:
Cp = 1200 [J/kgK]
Cond = 0.23 [W/mK]
Density = 1900 [kg/m3]


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Free code

This program is freeware. It works on Windows 95 and later.

Bcond, thermal conductivity calculations for PCBs. Download.