Re: [SI-LIST] : Serpentine traces

D. C. Sessions (dc.sessions@tempe.vlsi.com)
Thu, 23 Apr 1998 12:10:14 -0700

Paul Thompson wrote:
>
> >Has anyone ever tried to simulate the effect of serpentine coupled lines in
> >SPICE?

> I have a related question: Let's say you have a big wide bus and you want
> to match the lengths of all the traces. Trying to put wide spacing between
> all the serpentine traces would obviously require lots of layers. As an
> alternative, what do people think of routing the "doubled-back" sections
> all on a different layer, preferably one on the opposite side of the same
> plane that the "main" traces are run? I'm assuming here that the entire
> bus switches at the same time.

Layer-to-layer manufacturing mismatch is pretty fierce, and then there
are the vias. Seems to me that getting the delays matched is going
to be a LOT of work, and will never be as consistent in manufacture
as double-back would be.

-- 
D. C. Sessions
dc.sessions@tempe.vlsi.com