PCB Libraries Forum : 0402 Capacitors Under 1 mm Pitch BGA https://www.PCBLibraries.com/forum/ Fri, 26 Jun 2026 11:59:46 +0000 Mon, 26 Nov 2012 17:28:02 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=695 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[0402 Capacitors Under 1 mm Pitch BGA : I think that they will fit...]]> https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2389.html#2389 Author: DaveCowl
Subject: 695
Posted: 26 Nov 2012 at 5:28pm


I think that they will fit with the Least Material selected - that brings the pad down to s50r10.

I also imagine that via in pad will cause a stir for the folks who see any added process to the PCB as expensive (even though we will have $400 FPGAs on these boards...). But I can see if it will fly.

Thanks!
]]> Mon, 26 Nov 2012 17:28:02 +0000 https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2389.html#2389 <![CDATA[0402 Capacitors Under 1 mm Pitch BGA : Turn on Rounded...]]> https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2388.html#2388 Author: Tom H
Subject: 695
Posted: 26 Nov 2012 at 5:01pm

Turn on Rounded Rectangle pad shape for the 0402.
 
Here is a 1 mm pitch BGA with dogbone fanout.
 
The 0402 can be perfect center via-in-pad or located in-between fanout vias if there's room.
 
 
 
I would go for the via-in-pad with plugged via. You can see where the Rounded Rectangle pad shape passes DRC clearance checks. Cap the via-in-pad with surface finish, planerize flat and ready for reflow with BGA fanout on one side and capacitor pad on the other side.
 
 
With capacitors, a small "dimple" (with trapped air) in the pad would not create a void cavity in the lead like they do in BGA via-in-pad. 25% void is acceptable.
 
 
]]> Mon, 26 Nov 2012 17:01:20 +0000 https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2388.html#2388 <![CDATA[0402 Capacitors Under 1 mm Pitch BGA : I guess a fifth option is...]]> https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2386.html#2386 Author: DaveCowl
Subject: 695
Posted: 26 Nov 2012 at 3:32pm


I guess a fifth option is to tolerate the vias being shifted slightly off grid... though this might be more problematic with the resistors when I try to place those as is...

]]> Mon, 26 Nov 2012 15:32:23 +0000 https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2386.html#2386 <![CDATA[0402 Capacitors Under 1 mm Pitch BGA : I know that it is possible...]]> https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2385.html#2385 Author: DaveCowl
Subject: 695
Posted: 26 Nov 2012 at 3:31pm


I know that it is possible to have 0402 parts under the via breakout for a 1mm BGA.

I am currently pondering how best to do this.

Right now I have s60r12 pads with v50h25 vias, and Expedition is nudging the vias slightly, indicating that I have cut things just a little too close.

I could do any of the following to fix this:

1) Smaller square pad (or go to Least Material rather than Nominal).

2) Reduce the clearance requirement

3) Larger radius making the pad more round

4) Smaller via pad and possibly hole

My resistor pads are actually slightly bigger again (r64_63r13) so they will need a little more of whatever is the best approach...

Ideally I would like to just have one 0402 cap footprint and one 0402 res footprint in the layout, but it would also be possible to have two of each, wuth a special one for under the BGA.

Any thoughts on this appreciated. 
]]> Mon, 26 Nov 2012 15:31:12 +0000 https://www.PCBLibraries.com/forum/0402-capacitors-under-1-mm-pitch-bga_topic695_post2385.html#2385