08.09.2020 | Technical topic

Layout Tipps & Tricks

Layout Tipps & Tricks

from developers for developers

Heat traps and heat sinks

 

Large copper areas in printed circuit boards dissipate heat and can lead to insufficient/uneven melting of the solder paste, or insufficient penetration. In this case the through hole is not completely filled by the solder. Likewise, large components can dissipate above-average amounts of heat and thus lead to an unsatisfactory soldering result.

For THT and SMT components with an increased heat requirement at one or more terminals, the heat input can be increased by designing the PCB accordingly. The same applies to the placement of vias in the immediate vicinity of components. In both cases, it is important to consider from which side the heat input occurs.

Wärmefallen für THT Bauteile

Wärmefallen für THT Bauteile

              

Wärmefallen für SMD Bauteile

Wärmefallen für SMD Bauteile

 

 

 

 

 

 

 

 

 



Unused pads should be removed on inner layers ("non functional pad removal"). For multilayers, layers with large copper areas should be placed as close as possible to the surface where the heat is applied.

Größentabelle

Größentabelle


NOTE: The greater the distance between pad and surrounding copper, the better the heat trap.


An additional possibility is the use of different pad areas on the TOP or BOT side for wave soldering. With large pads a good heat input or heat dissipation is achieved. An opposite effect occurs with smaller pads.

By appropriate combination (large pad on the solder source side, small pad on the solder destination side) the solder penetration can be improved.

Einfluss der Pad Größen auf BOT und TOP

Einfluss der Pad Größen auf BOT und TOP

More tips and tricks from 30 years of experience in electronics production can be found in our  EMS Design Guide. Our practical little helper is now available in 3rd edition.

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