copper thickness test

Should we be using double vias to get good reliability?

Wodehouse said that he didn't so much enjoy writing, as he enjoyed editing and tweaking it to perfection. It shows in his writing. It's amazing how perfectly he put together a few common words.

Hope you like it. It's a silly romance that is wonderfully written.

Personally, I still like paper books.

One test case: via is specified 15 mil drill, on a 62 mil board, ENIG, specified 1 oz copper. I see 417 uohms side to side and figure there's an equivalent of 1.3 squares of copper in the via. That's about 320 uohms/square, or about 1.5 oz copper, if I did all that right.

We find vias to be very, maybe perfectly, reliable from a good board house. If any one flubs a single via, we won't buy from them again.

That is lower than I first expected but agrees well with Saturn PCB Toolkit which predicts 430uohm for a 2mil plating thickness.

piglet

Most stuff from that era was superbly crafted. 'The Go-Between' in particular springs to mind in this regard.

Same here. I'll probably never, *ever* buy a Kindle.

I have heard people argue that one from time to time. But IME it doesn't work, a good PCB fab will deliver 100% reliable vias. A bad one typically suffers from 'popcorning', where air voids in the laminate blow the layers apart when the board goes through the reflow oven.

If the void is near a surface layer, if you're lucky you can see a bubble. Any vias in the area will be permanently or intermittently O/C, the intermittent ones were a nightmare.

If the PCB vendor can't or won't address this issue, fire them.

Because the affected area is typically the size of a penny, mutliple closely-spaced vias for the same net won't help. The only reason I use multiple vias is to reduce inductance or thermal resistance.

My use-case for a Kindle is only for those occasions when a book is insufficient.

I leave it in my daypack in case I get trapped somewhere for too long with nothing to read.

I use it for classic books that I might like to read but am not prepared to buy and keep around the house "just in case".

I have never paid for anything that's on the kindle. Project Gutenberg is a wonderful resource.

For signal contact there's no issue; to carry current you'd have to run the numbers.

RL