Screaming Circuits: June 2010


Ten Things for an Engineer to consider now that summer is here

Now that summer is here... I should caveat that a bit. Summer just started last week here in the Pacific Northwest. It's been one of the wettest and coldest springs in quite some time. I should caveat that too. "cold"... Read more

Vias between BGA pads

I ran across a question posted on the Xilinx forum recently about whether vias in BGA pads needed to be capped, as suggested in my post about that subject. We do recommend that the vias be filled and capped with... Read more

Extra Fine Pitch BGA pads

One of the annoyances of the world of trade secrets and proprietariness is that we can't all learn from each others' experiences. That is important and even generally necessary in a competitive world. If you put in some hard work,... Read more

Another Via-in-Pad reason

Just the other day - No not that one. The other one - I was reading through some of the open source Beagleboard information again and I came across an interesting tid bit. In one of the early revisions, they... Read more

How to Fill a Via

We here at Screaming Circuits keep telling people to fill and plate over vias in BGA pads. The same goes for small passives too, like 0402s and 0201s. As I closed in this post, best option is to fill and... Read more

Via in pad - tenting the bottom side

Speaking of vias in pads, here's a reason we're not terribly fond of the technique of using solder mask to tent the bottom side of a via in a BGA pad. As I mentioned in my last post, capping the... Read more

Large Via In Pad

I haven't written about via in pad in a while, but the issue hasn't quite gone away yet. This particular QFN, to the left, has the vias tented, which is good. However, it could be better. If you look close,... Read more

Underness as a Common Theme Again

I didn't mean to, but here I seem to be with a common theme again. Like yesterday, and again not too long before that - parts under parts seems to be the thing of the hour. Maybe the caps are... Read more

Underlapping Parts

Sometimes, it's the simple things in life that we must stop and appreciate. Like the fact that just because there aren't any pads in a spot, doesn't mean that you can use the space. Take this PCB, for example. U3... Read more


I remember back in the olden days when we didn't have any space and everything needed to be abbreviated or put into obscure symbols. We had eight characters for file names, plus a reserved extension. So, for example, on disk,... Read more

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