SMT prop and single sided PCB

Graham Stabler

I'm making a very light weight propeller platform on a flexible laminate (like mylar but heat proof), I need to use the surface mount version of the propeller but obviously need to be careful about the ground loops to protect the PLL. I can probably do a double sided PCB but vias under the propeller are probably not practical. Any suggestions on a reasonably robust layout?

I have several less than professional ideas if I get stuck but I wanted to check before getting desperate.

OK before I posted I tried one idea for a low profile via, I cut a short slot in the laminate with a scalpel and pushed a rectangle of copper film through the hole, folded down on each side and then soldered before the excess was removed with braid. Works quite well, might be an option.

Graham

Tubular

Sounds interesting. Are you using the QFN prop? Because as I see it, that leads you to have a big ground pad common underneath, no vias under the prop, and radial Vdd's.

If using the TQFP there are of course many options. There was a recommended design block posted some time ago by Parallax to minimise PLL failures.

Graham Stabler

I am using the TQFP. The recommended design is double sided and includes vias under the propeller which is the problem I have been trying to solve.

Graham

Graham Stabler

Ah So I suppose if I use the QFN then that does mean vias around the prop which would be easier. Not easier to solder though!

Graham