Pointer needed for IC thermal pads

Thread Starter

MaxHeadRoom

Joined Jul 18, 2013
28,488
Just exploring for the first time, an application where the IC requires a thermal pad.
Does any one have any pointers to info on the subject.
For example, IC literature show a PCB plated area under the device, how is this indicated on the relevant Gerber file.?
Also is a separate thermal pad also used?
Is the pad typically referenced to power common?
Tips appreciated.!
e.g.
1693065952759.png

. 1693065875712.png
 

Thread Starter

MaxHeadRoom

Joined Jul 18, 2013
28,488
Thanks, I took a look at one of the KiCad footprints and they show similar, adding Vias in a bare copper heat-sink pad.

1693071949129.png
 

Ian0

Joined Aug 7, 2020
9,433
The thermal pad is generally numbered n+1 where n is the number of normal pins. It is generally connected to 0V, but not always.
Pay careful attention to the stencil and solder resist recommendation s in the datasheet - if you get too much solder paste on there it gets everywhere and shorts things out, or makes a big blob on which the device floats preventing the normal pins being soldered to their pads.
If it's on a SO8 or similar you can extend it to a large pad area on the component side, but KiCad generally adds thermal vias to connect it through to a ground plane.
 
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