Cooling techniques and heatsink mounting proposals

TN1037

10/24

DocID024655 Rev 3

Figure 10. Large heatsink pasted on the package

In order to ensure safe working conditions, as previously stated in

Section 1.3: Safe

distances, the adhesive foil or the thermal rubber must be placed to improve electrical

isolation and therefore must be properly sized in order to increase the creepage and

clearance distances.

2.3

Heatsink bonded on the PCB by mounting screws

The heatsink can be also bonded on the package and fixed on the PCB using one or two

mounting screws (

Figure 11), ensuring a firmer assembly process. The use of this heatsink

with dedicated form factor prevents any possible stress on the leads of SLLIMM-nano and

the PCB soldering pads. This technique requires the use of a thermal pad between the

heatsink and the topside of the SLLIMM-nano in order to ensure the creepage distance. A

safe distance between the shorter side of the device (where some trimmed terminations are

placed) and the heatsink must be guaranteed in order to ensure clearance. The two screws

option is preferred in order to improve mechanical stability and reliability of the system. Any

mismatch in thickness between the SLLIMM-nano and the heatsink can be resolved by

using a thin insulated spacer between the device and the PCB.