Weird warning messages when using spectre with AMS hitkit

S

spectrallypure

Guest
Hello all, I always get the following warnings when simulating my
design within the Analog Environment using spectre and the AMS design
kit (fb mode, tech file C35B4):

[Notice from spectre in `modn', during circuit read-in.
modn.mosinsub: `jsw' has the unusual value of 130 pA/m.
Notice from spectre in `modnm', during circuit read-in.
modnm.mosinsub: `jsw' has the unusual value of 130 pA/m.
Notice from spectre in `modpm', during circuit read-in.
modpm.mosinsub: `jsw' has the unusual value of 610 pA/m.
Notice from spectre in `modp', during circuit read-in.
modp.mosinsub: `jsw' has the unusual value of 610 pA/m.
Notice from spectre in `modnh', during circuit read-in.
modnh.mosinsub: `jsw' has the unusual value of 130 pA/m.
Further occurrences of this notice will be suppressed.]

Does anybody know why is this, what does it mean, and how to
correct/suppress it? The simulations continue to run despite these
messages, and the results seem to be congruent with what is expected.
Moreover, I searched for the parameter "jsw" in the model files listed
(modn, modnm, etc.) but IT DOES NOT APPEAR IN ANY OF THESE MODEL FILES
(bsim3v3 models)!!! Why does spectre say that jsw takes those values,
then? Where do these values come from?

Regards & thanks in advance,
 
spectrallypure wrote:
Hello all, I always get the following warnings when simulating my
design within the Analog Environment using spectre and the AMS design
kit (fb mode, tech file C35B4):

[Notice from spectre in `modn', during circuit read-in.
modn.mosinsub: `jsw' has the unusual value of 130 pA/m.
Notice from spectre in `modnm', during circuit read-in.
modnm.mosinsub: `jsw' has the unusual value of 130 pA/m.
Notice from spectre in `modpm', during circuit read-in.
modpm.mosinsub: `jsw' has the unusual value of 610 pA/m.
Notice from spectre in `modp', during circuit read-in.
modp.mosinsub: `jsw' has the unusual value of 610 pA/m.
Notice from spectre in `modnh', during circuit read-in.
modnh.mosinsub: `jsw' has the unusual value of 130 pA/m.
Further occurrences of this notice will be suppressed.]

Does anybody know why is this, what does it mean, and how to
correct/suppress it? The simulations continue to run despite these
messages, and the results seem to be congruent with what is expected.
Moreover, I searched for the parameter "jsw" in the model files listed
(modn, modnm, etc.) but IT DOES NOT APPEAR IN ANY OF THESE MODEL FILES
(bsim3v3 models)!!! Why does spectre say that jsw takes those values,
then? Where do these values come from?
Click to expand...
I don t have the models visible right now, but it looks to me like the
warnings come from a parasitic device meant to model latchup. That would
explain the unusual parameter value.
 
Thanks for the reply, Fogh.

Well, as I stated before, I am pretty sure that the model files don't
specify this parameter -at least not explicitly. Is there any chance
that the model files link to other specification files during
simulation time, where this parameter is (mis)defined? You mention that
it could be modelling parasitics... is there any simulator
switch/parameter that I could use in order to disable the use of this
parasitic device (which I haven't included explicitly in my design)?

Best regards,
 
spectrallypure wrote:

Well, as I stated before, I am pretty sure that the model files don't
specify this parameter -at least not explicitly. Is there any chance
that the model files link to other specification files during
simulation time, where this parameter is (mis)defined?
Click to expand...
Looking in the model files I have it is certainly defined. Are you sure
you have the latest versions? Mine are revision 3.2. jsw is mentioned on
lines 79 (modn), 157 (modnm) and so on.

I'm looking in $AMS_DIR/spectre/c35/cmos53.scs

Cheers,

Roger
 
You are absolutely right, Roger!
I misinterpreted the model paths and thought the simulator was using
those located under $AMS_DIR/spectreS/c35/cmos53/tm/ but a further
review revealed that in fact I was using the cmos53.scs file that you
point out. Clearly the confusion arose from my past ignorance about the
differences between spectre and spectreS, which I didn't learn until
very recently.

So... the conclusion would be that the value 1.3e-10 for the "jsw"
parameter is in fact correct for this AMS process? Why does Spectre
complain, then?

Thanks a lot for your help! :)
 
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