[sdiy] PCB files

[Tim Parkhurst]

On 3/5/07, Charles Bisaillon <sdiy at oveloe.com> wrote:
> So my team mates have finished the PCB files with only few thing to fix. But
> they followed only half the PCB design guidelines from Joe Grisso that I've
> posted for them. The trace size is alright, the PCB size is alright but the
> component placement is horrible (for trace length) and they finished them
> off with autotrace and 2 layers. Check it out.
>
> http://www.oveloe.com/490/VCOpcb.JPG
>
> I have never done this before but, according to the guidelines, this PCB has
> major problems. But on the other hand, the breadboard is surely worst with
> all those stray capacitances, but experimentally, it was a bit noisy but
> really not that bad (on my 10$ cpu speaker).
>
> I am asking those of you who have experienced this before. Is this
> acceptable? Would any of you consider this good work? I really am new to
> this and thanks a lot for your help.
>
> Charles
>

Hi Charles,

My guess is that this board will work, but you'll get a fair amount of
interference or noise (especially if you've got very high frequencies
running around). If it's only audio, it won't be quite as bad, but
there's a lot of back and forth, and you're right, the traces are a
lot longer than they should be. Unless time is really short, I'd think
about going back and redoing this one with the components grouped
functionally (i.e. put the Rs and Cs next to the ICs they work with).
Generally, the placement you have is not correct. Plan it out on paper
first, try to keep the 'functional blocks' together, and also place
the blocks to minimize the trace lengths. Some other good advice is to
route the power traces first (keeps them short and direct). Don't
forget plenty of bypass caps!!

Tim (short and direct) Servo
-- 
"Imagination is more important than knowledge." - Albert Einstein