No thermal relief at high current DC-DC converter?

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Mercury

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thermal relief rules -patent

Hello,
I have a DC-DC converter PCB where there are high currents. If I do not use thermal relief on the pads, will there be any problems with soldering? Anyone has any experiences?

Best regards
 

pcb thermal relief rule

Hello
It depends from kind of pads without thermal relief. In case of THT it shouldn't be a problem but in case of SMD it depends from manufacturer. Few rules which help you to design a layout without thermal reliefs:

- in case of SMD components like resistors or capacitors (without thermals) both traces shoud be the same size - it will help to avoid tombstone effect
- absence of solder mask - it increase cooling but for soldering point of view it may be a problem (especially in case of ICs with thermal pads). Try to have small area of solder mask close to soldering pads.

If you have some questions please ask.

Best regards
 

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    Mercury

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thermal relief tombstone

I've layed out a lot of DC-DC converters (up to 14 Layers with 3oz inners) I've never used thermal relief on the vias or on SMD pads & I've never had an issue with reflowing of SMD's. It a different story with PTH I/O pins I'd recommend thermal relief if there are more than 1 or (at a push 2) planes connected to the pins especially if they are manually soldered.
 

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    Mercury

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Re: No thermal relief?

HI,
as i m new to pcb design and layout..can you clarify some doubts..

1.where/why do we use thermal relief pads.
2.do we use it for both thru-hole components as well as smd components
3.do we use thermal relief pads for both power as well as signal lines
4.do we use it for tracks as well as planes
5.what is tumbeffect
 

No thermal relief?

hi Mercury,
my experience no need thermal relief for flow soldering methods.

but if u used reflow soldering method should be use thermal relief.because the input and output pads copper volume is should be same condition.any difference is there u ready for facing the solder problems in smd components.
 

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