[SI-LIST] : delay lines

smithh@VNET.IBM.COM
Wed, 24 Sep 97 15:38:41 EDT

The 2nd order effect that Andy alludes to is what I call current jumping
in a zig-zag pattern. Primarily due to inductive coupling, the active
signal induces a return current on itself which due to the zig-zag pattern
propagates in the same direction as the active. The outcome of this effect
is a net delay decrease.

So when you force wire in a zig-zag pattern to obtain a certain net delay(i.e.
for clock balancing, etc.) and expect a To*L result, be careful. You may have
just added an unwanted skew in your clock distribution
or pop up early mode surprise in your design.

> ...
> What about second-order effects; for example, does the little zig-zag
> approach allow a weaker wave mode to zip right along as if the
> zig-zags weren't there?