🚀 go-pugleaf

I am looking for some simple MOS circuits that are difficult to simulate
with SPICE-like circuit simulators. I need this because I'm implementing
the infamous gmin stepping algorithm in a multilevel circuit simulator
that I'm developing for my thesis. In particular, I'm interested in MOS
circuits that will not achieve convergence with Newton-Raphson, but that
will converge with the gmin stepping algorithm. Our simulator at present
can only do .OP and .DC sweep analyses and handle SPICE LEVEL 1 mosfets,
so please submit only circuits exhibiting convergence problem with these
type of analyses and device model.
What I'm looking for is a simple circuit (<= 10 devices) for which it is 
known that it will get to convergence ONLY with gmin steppping.
I'm aware that circuits with positive feedbacks (e.g. static MOS SR
flip-flops) are hard to simulate with existing techniques.

Descriptions files in SPICE format are welcome.

I will summarize any reply to the Net.

Thanks,

-Arrigo Benedetti
-- 
Arrigo Benedetti             e-mail: arrigo@cube.sublink.org (preferred)
University of Bologna                benedett@deis01.cineca.it
undergraduate student (EECS)         
Via S. Agata, 11               Tel:  (home)   +39 59 224929
41100 Modena - Italy                 (office) +39 59 216688 (fax) +39 59 220727