Callback for instance parameters

Hi,All

I have a problem that has bothered me for a while that is caused by the
design kit for icfb.

Why do many design kits use callbacks in the CDF to calculate parameters
such as source/drain area of transistor?
When things are implemented this way you can not use some functions in
the simulator. For example you can not sweep the width of a transistor
and get correct results because the parasitics were calculated for the
initial width in the schematics

Would it not be better to implement such function in the models? So that
functions such as sweep can be used.

This is no big problem but it makes the tool more difficult to use.

Regards,
Andreas

 

Good man! Glad to see someone else who sees the problems from
the dreaded callbacks!

I've made some comments on this in the past:

http://groups.google.com/groups?q=c...&selm=&rnum=3

http://groups.google.com/groups?q=&rnum=4

Unfortunately (as I've pointed out before), they appear attractive
for kit developers, but often they're not the ones using the tools...

Andrew

 

I colud not agree more with you!

But why do certain kit developers who know better still use them?
As you stated in your earlier comments they appear very attractive. But
if they limit the possible usage of your other products. One would think
that one would try to use other ways of implementing such functions then
it is possible.

I have used your skill code example from your earlier comments to get
around the problem. But if I run lots of short simulations and change
the schematic in database between every run the time consumed by
changing the database,netlisting and other stuff will be significant. If
one instead could use the alter (or other) function in spectre you would
not need to change the database or renetlist at all!

Andreas