Electronics > PCB/EDA/CAD

Connecting TOP and BOTTOM layers with 0402 components IN a non-plated hole??....


I was looking for something completely different, when google returned this patent in a search results:
"Integrating capacitors into vias of printed circuit boards"

That's interesting, but it got me thinking. 

An 0402 size component is the following size (in inches)

Code,   Length (l),   Width (w),   Height (h)
0402,   0.04,   0.02,   0.014

If I had a normal 62mil thick board and I were to make a non-plated hole that's around a 25mil hole and 40ring 48mil hole and 70mil ring, I bet I could drop an 0402 down in the hole. 
I could then solder it from both sides and have a direct connection without all the nasty via inductance, capacitance, resistance, etc.

Is this a thing?  Does anyone do this?

Note: I got the required hole diameter wrong to clear the corners of the part.  Oops.  Still interesting.

Still would have the same inductance of the component. Has been done with components integrated into the board in layers, normally some esoteric high value boards, where they silk screened resistors onto inner layers, so that they could be fully shielded with a ground plane either side, and integrated capacitors as well. For a multilayer board going to be doable, but will not be a part you can autoplace, you would need to place each one, solder the one side, then solder the other, and still have to worry about flux residue in the hole causing problems down the line. But if you want, just make 2 plated vias next to each other, and mill the gap between them, like in a mouse bite, and then you can slip the component sideways in and get it soldered and cleanable. Might even be able to use solder paste dots each side, and slip the component in, and let the flux and surface tension hold the component in place during reflow.

Only thing I can see this doing well is to put capacitors onto a BGA pin, where you have an internal to the BGA power feed, and want a low inductance ground, using a larger hole to expose the ball, and having the BGA package glued to the board, so the capacitor can stay in place for reflow. But even there easier to simply route the via to the capacitor, as a capacitor that critical is better integrated into the BGA interposer itself, or on die as a silicon capacitor.

Now I want to use it in a future design. But seems like a pain in the ass to keep track of. I guess the easiest way is to have a dedicated footprint for it.

Would 0603 work better though?



--- Quote from: thm_w on March 23, 2023, 09:51:47 pm ---...
Would 0603 work better though?

--- End quote ---
You would need a bigger hole.
Funny, I just did the math on the size hole you actually need to clear the corners of the parts.  I was off by a bit.
0402 = 45mil hole
0603 = 68mil hole


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