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To Thermal or not to thermal ...

Former Member

Is there any pros or cons for turning off the thermals on a GND layer?  I'm noticing when there are components close together, sometimes the thermals just don't make the connections needed, but by turning off Thermals on the layer, it works just fine.  So, pros?  Cons?

  • 0

    There's a good summary of thermal relief pads at Wikipedia: http://en.wikipedia.org/wiki/Thermal_relief

     

    Basically, if you don't have a thermal relief pad, then when you try to solder to a ground pin the heat from your soldering iron conducts to the entire board and it's really hard to get that pin hot enough to solder properly.  The spokes on the thermal relief pad resist the flow of heat, allowing the pad to get hot.

     

    If your thermal pads are overlapping because two ground pins are close together, you may want to connect the ground pins on the component layer and share a single via to the ground plane.

  • 0 in reply to johnbeetem

    Ah, yes, I had forgotten about that aspect of it.  A little bit of shuffling things around doesn't hurt, so I did just that.  The issue here was that I had a ground pin from an MCU close to two ground pins for capacitors.  The capacitor pins tied together and to the GND layer nicely, however the MCU pin didn't tie itself to anything.  It didn't tie to the GND layer because the caps were too close, and it didn't tie itself to the pins on the caps either, so it was left unattached.  By moving the caps just a little bit out, it was able to fill in and the MCU pin connected fine.