The recommended land pattern of a part I’m making in Eagle mentions an “array of solid vias”. Is a solid via different than a regular via?
See note 3 on page 77 of:
It probably means vias that are filled with copper or something, which gives the best heat transfer between ground polygons on top and bottom layers.
Just try to use the smallest hole size you can, so that solder doesn’t seep through the holes when you reflow. You could manually fill them with solder afterward if you want, or just leave them; it’s probably not a big deal.
Ah, that makes sense. Thanks Allan.
This link has a bit of info about such vias: http://www.remtec.com/smt.html
Since the maximum power consumption of that chip seems to be less than 200mW, I wouldn’t bother with such vias, or filling them with solder.
Just put a bunch of vias using the smallest hole size your supplier offers (within reason - no need to use laser-drilled vias). If you “tent” the vias on the other side of the board (ie, cover in soldermask), this will reduce the amount of solderpaste that is “stolen” by the vias.
We know what vias are, the question was about solid vias.
Yes, they are different.rusttree:
Is a solid via different than a regular via?
Many people specifically note to the PCB fab that they want “all vias plugged and tented”.
Often they don’t really need every via to be completely filled (plugged) and tented over with solder mask, but it is less work to treat them all the same rather than give some holes a different treatment than others.
Other times – such as when the assembled boards will endure vacuum-based bed-of-nails testing – it is convenient if every via is plugged, so there is no holes left for air to leak through.
While in theory filling thermal vias with copper would in principle give the best heat transfer, the last time I checked it was highly discouraged because of reliability problems. Instead, the PCB board manufacturer makes “plugged” vias by filling vias with polymer solder mask.
Has anyone figured out how to fill PCB vias with metal without reliability problems?
In my experience, if you don’t specifically tell the PCB fabricator how you want your vias – filled or not --, sometimes you’ll get boards with all vias filled anyway, sometimes you’ll get boards with only a few vias filled, and occasionally you’ll get a board without any vias filled. You can see a tiny hole all the way through the non-filled vias.