Recommended VIA size for nrf52810-caaa

[vkbakken]

Can Nordic please recommend/share reference design size of VIAs used with CAAA package? Drill size and shoulder.

[Julian]

There are two designs (2 layer, 4 layer) in the reference layout project zipfile for the CAAA that you can download from the nordic product page for the 52810.

I opened up both the projects in Altium, and both have 0.25mm holes on 0.5mm copper. 

[vkbakken]

Tanks for the reference - but this reference design(s) assume that vias are in pad of the CSP. Getting a bit of pushback from PCB house on that they do not prefer via in pad.

I should have clarified the request to be proper via between balls/pads if there were a recommendation

[Julian]

oops! sorry I made a mistake - the vias in pads are actually 0.3/0.1mm didn't see that when I quickly checked last night. 

Good luck with your manufacturer... I expect that capped vias is going to be the simplest approach to deal with something so fine already, rather than trying to shrink down copper to copper clearance and hole to copper registration.

I'd be worried about the effects of attempting dogbones, like was suggested here. Unless your manufacturer can suggest an escape routing pattern and reduced clearance, via size, and annular ring rules that suit their process.

Have you considered another manufacturer might be able to do what you need better?  Or a QFN part might be a better fit for your current manufacturing service capabilities? 

[Andreas]

Hi,

 

The size in the reference design is not more special than what we have used in all internal (and external, if applicable) designs, meaning at least it works fine for our EMS. This should not be read as a hard requirement from us, you should still run it by your manufacturer and make any adjustments if they have any experiences with their equipment.

Depending on your design, and how many pins you plan on using, you might be able to route signals out between the pads of the outermost pins. Other than that, the size of this part unfortunately limits the alternatives.

 

Best regards,

Andreas