SPICE Convergence Tricks - Consequences?

Once again, a big thanks to all who replied to my last question. :-)
I've been using several tricks to try to solve SPICE convergence
problems:

-adding a 0.001ohm resistor in seris with the stimulating source
-increasing the value of the ITL1 to 300-500. (more iterations allowed)
-relaxing ABSTOL
-decreasing the sweep of the stimulus (I couldn't quite get this one to
work)

Many people mentioned that convergence problems are quite common, I would
like to know how common are they?

Furthermore, I am curious if anyone has a convergence fix that works
everytime, as it seems tedious to try to get things to converge everytime
just by trial and error fixes.

Also, what kinds of side-effects, or problems (in terms of IBIS
modelling) have people encountered by forcing the analysis to converge via
fancy SPICE tricks?

One last question regards clarification about typ, min, and max
curves. When one is generating curves for the typical case,
suppose the typical case passes but both the min and max fail, the columns
should read NA for min and max right? Now should I go back and try to
tweak the min and max to converge? OR are some curves meant to only work
for the typical case?

Many thanks in advance,
Regards,

roland

*************************************************************************
*Roland Chang | email: roland@sfu.ca *
*Simon Fraser University | OR *
*School of Engineering Science | chang@pmc-sierra.bc.ca *
*3rd year Computer Engineering Option | *
*************************************************************************

 
Received on Tue May 20 13:02:58 1997