Let's say that 4 layers is the max(I have no other choice - cost...) but
EMC is still a requirement. This stack-up(below) is specified, Is there
anything to be done? Would hatching the pwr and gnd planes be an option
that would actually help?

Scott
IDS


Douglas McKean wrote:
>
> At 01:09 PM 10/27/98 -0500, Chris Ball wrote:
> >Hi Doug,
> >
> >>          Component Side
> >>
> >>             trace
> >>S1    IC#1 --->---+    +-->-IC#2
> >>Gnd  ---------<---|----|--<-----
> >>Pwr  ??? ---------|--<-|---- ???
> >>S2   -------------+-->-+--------
> >>
> >>          Solder Side
> >
> >So what's a better way? Another ground layer between Pwr and S2? Please
> >elaborate when you have the time.
>
> Well, yes ---> if it's allowed <---.
> Then, sock the ground planes down to
> one another with plenty of connections.
>
> My personal preference to start *any* stack up with
>
>  Gnd  ----------------
>  Pwr  ----------------
>  Gnd  ----------------
>
> as a cornerstone for the entire board layout.
> Then add extra signal and ground layers above
> and below this structure.
>
> *** This is obviously not a hard fast rule. I.e. what's
>     the cost differential between a 4 and 5 layer board,
>     or between a 6 and 7 layer board?
>     <I ask rhetorically sort of chuckling ...>
>
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