Assembly Instructions
AN2009-01
Condition of the Heat Sink for Module Assembly
Application Note 16 V2.2, 2015-02
7 Condition of the Heat Sink for Module Assembly
The power loss occurring in the module has to be dissipated via heatsink in order not to exceed the
maximum permissible temperature T
vjop
specified in the datasheets during operation.
The condition of the heatsink surface in the area where the module is mounted is of great importance,
as this interface between heatsink and module is of decisive influence on the heat transfer of the entire
system.
The contact surfaces, the surface below the module and the surface of the heatsink, have to be free of
degradation and contamination to prevent excess mechanical stress to the module as well as an
increase in thermal resistance.
Heat sink requirements:
Roughness: ≤ 10 µm
Flatness based on a length of 100 mm: ≤ 50 µm
Note 1.: The flatness of the heat sink should not exceed the values listed above. This area
includes the entire module mounting area as well as that of the clamps.
Note 2.: If the layer of thermal grease is applied too thick, e.g. as a consequence of cavities, the
thermal resistance R
th
between module and heat sink will increase.