N 2010-03
r 2009
Application Note AN 2010-08
V2.0, August 2010
PLEASE NOTE. The heat sink design should be done in such manner in which the cooling
fluid has reduced bypass possibility.
The figure below presents the cross section view of HybridPACK
TM
2 module and the heat
sink. This cross section shows that certain distances have to be minimized so that the
cooling fluid can not bypass the pin fin structure. One of the critical places is the border
region between the pin fin structure and the heat sink wall shown in the “A” area
(represented in the figure below with the black colour). If the distance between the pin fin
structure and the heat sink is too big it will offer unwilling path for the fluid. This will
eventually decrease the cooling performance. The second critical path is the gap between
the pin fin structure and the bottom of the heat sink (represented in the figure below with the
red colour). This gap should be minimized as well.
Figure 8 Cross section view of HybridPACK
TM
2 and the heat sink. Within the shown
area “A” certain distances should be minimized in order to obtain
optimized cooling performance.
5
Screws to Mount the Module to the Heat Sink
To mount the module the following screws are recommended: DIN M6 screws which comply
at least with class 6.8 (for example, according to DIN 912 (ISO4762), ISO 7380, DIN 6912
and DIN 7984) in combination with a suitable dented edge washer and spring washer (for
example, according to DIN 433 or DIN 125) or the combination of both the “dented edge
washer”. The diameter of the used washer is 10mm.
The clearance and creepage distances specified in the HybridPACK™ 2 datasheets are the
shortest clearance and creepage distances existing at the unassembled and unconnected
module.
When selecting suitable M6 screws, washers and spring washers to mount the module, it is
recommended to consider the resulting clearance and creepage distances between the
power terminal and the nearest bolt head or washer during the development phase.
