Is it safe to use the exposed heatsink pad of a QFN to also connect the ground pins of the IC? (Like this question, but in my case the pad has many vias connecting it to ground plane.)

Additionally, is it ok to use the very same vias in order to connect components with the ground plane or the heatsink pad and its vias should be dedicated only to heat dissipation?

Edit: According to the datasheet the pad is connected to ground and should be connected to the ground plane:

"The centre pad on the base of the FT601Q is internally connected to GND, the PCB should connect to ground and not have signal tracking on the same layer as chip in this area."

In the image below it's the quarter of the QFN demonstrating my question (the blue component is a cap on the opposite side:)

enter image description here


It will say in the datasheet what the pad is electrically connected to.

You don't need dedicated electrical and thermal vias, just make the hole small (<0.3mm) so they don't wick solder away, but that is true of any via in a pad.

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  • \$\begingroup\$ I updated the question \$\endgroup\$ – Manos May 3 '19 at 15:37
  • \$\begingroup\$ Just to clarify, you mean I can proceed the way it is now, right? \$\endgroup\$ – Manos May 3 '19 at 16:17
  • \$\begingroup\$ ye its fine to place vias there. If you want to make sure regarding the solder thingy you can go for "vias in pad" technology which basically means that the vias are filled, leveled and the metallization is covering the whole area but this is rather costly and only required if the correct solder amount is really an issue (e.g. for BGAs). \$\endgroup\$ – Christian B. May 3 '19 at 16:26
  • \$\begingroup\$ @ChristianB. OK thanks, I didn't know that! My main concern was if those vias should stay dedicated to the the heatsink pad and not be used by any other components as a means to connect to the ground plane. \$\endgroup\$ – Manos May 3 '19 at 17:14
  • \$\begingroup\$ Actually connecting to ground (if allowed) is a superb way to deal with (moderate) heat as the ground plane is typically one of the biggest copper planes area wise and with low (electrical) resistance. Coincidentally good electrical conductor are typically good thermal conductor as well. \$\endgroup\$ – Christian B. May 3 '19 at 19:16

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