[sdiy] PCB layout tips

[Scott Juskiw]

Regarding the ground plane and the star ground, (BTW this is an all 
analogue layout I'm doing)...

Do I connect up the grounds to the chips (and other components) in a 
star, and _then_ fill up all the empty spaces with a ground plane? Is 
it OK to connect the ground plane to the nearest star ground point as 
long as I don't make any loops? Or is the ground plane one 
continguous sheet of copper that is completely separate from the 
star? Am I over-analyzing this?

Thanks for your help, I don't want to screw up too badly on my first attempt.

At 4:12 AM +0100 2002/12/16, Theo wrote:
>I often do this, IMO it simply makes for the easiest layout.
>However having a ground plane under your ICs may help prevent noise
>problems.
>Sometimes e.g. with higher resolution DACs having the ground plane under the
>IC is often mandatory.
>With double sided layouts my usual way is to have a ground plane under the
>ICs on the component layer and the power lines on the solder side.
>
>As for a do and don't list:
>- Use a "star" ground layout as much as possible
>   (in practice more likely a mix between "star" and "not star")
>- Do not mix digihell and Analogue, especially the grounds.
>- Keep they traces short.
>- Use a star ground layout.
>- Don't run stuff in parallel that could influence each other.
>    (extreme example; a digital clock parallel to microphone signal)
>- From about 20Mhz and up keep digital traces that belong together the same
>lenkt,
>   even if this means you have to make a silly to and fro pattern with one.
>- Did I already mention to use a "star" ground layout?
>- Use ground planes.
>- Don't make "loops", traces should NEVER come full circle
>   (ok there _are_ exceptions, but few and are _exceptions_)
>
>Theo
>