Additional information
22 of 31
Revision 4.0
2021-10-11
Recommendations for board assembly of Infineon transistor outline
type packages
Mounting of through-hole devices
Figure 16
Effect of torque on the R
th
value between package and heat sink.
Double sided heat sink mounting
Double-sided heat sink mounting is not recommended. In case of unsuitable mechanical heat sink properties,
high mechanical stress may occur, resulting in package damage as shown in
Figure 17
Negative effects of double-sided assembly on improper heat sink material.
Heat sink clip mounting
The clip mounting method has become popular because it is simple and reliable. The process is fast and
appropriate for mass production assembly. The screw mounting is applied at one end of the package during
fastening and can cause uneven contact pressure and bad thermal contact, whereas the clip is mounted on the
package center and therefore results in more uniform contact pressure as shown in
In case clips are used, the contact area between the plastic case and the clip is important. Clips should be
round or smooth in the contact area to avoid concentrated loads on the plastic body of the package.
For some applications it is necessary to have the package electrically isolated from the heat sink or PCB.
