This one shows holes and heat sink pads under the thermal vias. It's the bottom mask - areas of exposed copper. The thermal pads are 1cm square. I forget now the hole diameter, maybe 4mm but if there is a good standard size let me know. (Don't measure here as this includes a ring around the hole)
With a flat heatsink it would likely be best to put some suitable tape over unpopulated holes just to be safe. Or if some thermal pads are used under the ASICs the heat sink may stand off enough. We'll have to see.
You may be able to register to the holes. There is a known tolerance on them but generally I've stuck down the stencil to something holding the board so it's to the board edge. You'll need to visually inspect, and it isn't hyper critical as the solder paste can even be messy and it'll pull into place due to surface tension and the mask preventing it going elsewhere.
I would love an smd barrel-jack! There seems to be some space left free left of the pci-e powerconnector?
If the pci-e powerconnector isn't populated, do you think the solderpoints would short on a flat heatsink? The soldermask adds some tiny space, and ignoring the thermal compound and oxide layer in between too.
edit:
About aligning:
The solder pads are tiny. What do you guys think, would the holes be positioned precisely enough to align the stencil with them? That would help a lot! If we can define a narrower tolerance for the (4 corner) holes I would gladly pay extra.
Yes, planned for barrel jack in space behind PCIe. Probably a couple decent sized pads there that could even just be soldered to, or other connectors could use. I have a datasheet for a 4UCON SMD barrel jack and also a Switchcraft one is available at Mouser for 8x the price.If the pci-e powerconnector isn't populated, do you think the solderpoints would short on a flat heatsink? The soldermask adds some tiny space, and ignoring the thermal compound and oxide layer in between too.
edit:
About aligning:
The solder pads are tiny. What do you guys think, would the holes be positioned precisely enough to align the stencil with them? That would help a lot! If we can define a narrower tolerance for the (4 corner) holes I would gladly pay extra.
With a flat heatsink it would likely be best to put some suitable tape over unpopulated holes just to be safe. Or if some thermal pads are used under the ASICs the heat sink may stand off enough. We'll have to see.
You may be able to register to the holes. There is a known tolerance on them but generally I've stuck down the stencil to something holding the board so it's to the board edge. You'll need to visually inspect, and it isn't hyper critical as the solder paste can even be messy and it'll pull into place due to surface tension and the mask preventing it going elsewhere.