Spice: NPN.tol ? NPN.match ?

So for .tol, you think the variation in IS would be +/- 0.75, then, right?

That's a reasonable guess. IT's a couple more keywords to google on, anyway.

Odd how this syntax is similar to binning.

New to me...but here goes...

Don't know about match but I can guess the NPN.tol as I have something similar in SS. My bet is that the NPN.tol IS=0.75 BF=.9 gives the amount to vary the base model in worst case and/or MC runs. The "match" probably allows two of the same devices to be varied by the associate value, e.g. one device's IS in 3% different from another.

Kevin Aylward snipped-for-privacy@anasoft.co.uk

I would guess that the values are 0.75 * nom, and 1.25 *nom

In SS I use slightly different syntax. e.g. in SuperSpice.lib

..MODEL Virtual_SSWC_NPN_XS npn(Is=2 Xti=1 Eg=1 Vaf=1.25 Bf=2.5 Ne=1 Ise=2 Ikf=1

• Xtb=1 Br=1 Nc=1 Isc=1 Ikr=1 Rc=500m Cjc=500m Mjc=1
• Vjc=1 Fc=1 Cje=750m Mje=1 Vje=1 Tr=750m Tf=750m Itf=1
• Vtf=1 Xtf=1 Rb=750m Re=750m Kf=500m _ss_comment=[These values multiply respective params of nominal devices in wc runs if no other model available])

..MODEL Virtual_SSWC_PNP_XW pnp(Is=500m Xti=1 Eg=1 Vaf=800m Bf=400m Ne=1 Ise=500m Ikf=1

• Xtb=1 Br=1 Nc=1 Isc=1 Ikr=1 Rc=1.25 Cjc=1.25 Mjc=1
• Vjc=1 Fc=1 Cje=1.25 Mje=1 Vje=1 Tr=1.25 Tf=1.25 Itf=1
• Vtf=1 Xtf=1 Rb=1.25 Re=1.25 Kf=1.5 _ss_comment=[These values multiply respective params of nominal devices])

For the worst case models.

The above are *defaults* for all biploars. However, In addition, you can also specify a specific model variation spec for a particular device by naming the model spec location in the actual model, e.g:

..MODEL Q2N2222_XN NPN(Is=31f Xti=3 Eg=1.11 Vaf=50 Bf=256 Ne=1.34 Ise=14f Ikf=50m

• Xtb=1.5 Br=3.175 Nc=2 Isc=750p Ikr=0 Rc=300m Cjc=7.3p Mjc=341.6m
• Vjc=750m Fc=500m Cje=22p Mje=377m Vje=750m Tr=95n Tf=332p Itf=10
• Vtf=30 Xtf=200 Re=300m Rb=30 Re=500m Kf=0 SSWC_FileName=[C:\SoftwareDevelopment\SuperSpice\Debug\System\Zetex.lib] SSWC_ModelName=[Kevin_SSWC_NPN])

The SSWC_FileName and SSWC_Model points to where the spec is, alternativly models can be made with names:

Q2N2222_XS Q2N2222_XN Q2N2222_XW

The weak and strong actual models are searched for first, then the custom ones, then the default ones.

The idea being that even if the user has set nothing up, some reasonable WC runs can be made automatically.

Kevin Aylward snipped-for-privacy@anasoft.co.uk

Here is the usual way Monte Carlo is done in a model file:

..MODEL N1 NPN (IS=5E-16 LOT/UNIFORM=90% DEV/GAUSS=3%)

• (BF=220 LOT/UNIFORM=50% DEV/GAUSS=2%)
• BR=0.7 NR=1...

...Jim Thompson

Damn, Jim. My PSpice user guide doesn't even get into it that much!

The SIMetrix simulation guide however covers a lot of possible ways to set things up, like:

..MODEL NPN1 NPN IS=1.5E-15 BF={180*GAUSS(0.02)*UNIFL(0.5)}

says the same thing for BF.

I can't find the part that tells why to use breakout parts. What's the deal on that?

I see that in PSpice, *it says* that for 2 parts with DEV=5%, one can go up 5% while the other goes down 5%, but in the SIMetrix manual it says they'll be within 5% of each other. Typo? Confusion? Different implementations?

Sorry, I wasn't very complete, I just plunked down a sample model from Semtech, the ONLY foundry I use that expresses model variations in Monte Carlo style, rather than with library corners.

I don't know what version you have, but I've posted, from my version

Newsgroups: alt.binaries.schematics.electronic Subject: Monte Carlo Models (from sci.electronics.cad - MonteCarloPSpice.pdf Message-ID:

The PDF posted is the model section from the PSpice reference manual, version 10.0, showing notation for Monte Carlo parameter stepping in PSpice device models.

I just received version 10.3, but won't have time to install until next week... I'm in my usual crash and burn mode ;-)

...Jim Thompson

Security in PDFs is pretty much meaningless as long as they allow printing. Just print to a PostScript file, then run thru Distiller.

Unfortunately apps writers are often not USERS :-(

I keep finding capabilities in PSpice that the support people don't know about ;-)

...Jim Thompson

That's also more than the 9.2 ref guide has buried under "Commands". Note that there was a separate user guide then and that's what I checked before.

From your snip (nice of people to leave the security off the ANs and such so we can do that :) ) I see they changed their wording to

I don't trust their docs. They should write for the feds.

SIMetrix has a better WC/MC capability as I see it. Same for the docs.

I've not experienced that. I've had a few with security set, so I couldn't do the standard "extract pages", but I could still print to PS and then distill (v4).

...Jim Thompson

I belive that Distiller will refuse to do its thing when presented with postscript derrived from an encrypted PDF. There may be other tools out there of course...

Charles.

No Jim, Why should that be? While the AEs work around the product all day, they don't actually get to do much USING the product that much, so that, when they get an actual design problem, they tend to over-prioritize it... 8-)

So, you do a lot more with it than they do...

Also, it helps that you push the envelope a lot!

I do tend to be a "demanding user" (aka PITA) don't I ?:-)

...Jim Thompson

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