Mail Archives: geda-user/2013/02/13/23:00:25
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Thanks John,
Would that mean I should be using 4 terminal MOSFETS and join the source to
substrate?
I'll try that with spice-sdb extractor.
On GNUCAP list I was suggested to use a plugin for gnucap for gEDA.
I just wanted to fixate my workflow so that I know what to do. I'm just
getting my feet wet on gnucap and ngspice.
Thanks for your suggestions.
On Wed, Feb 13, 2013 at 3:39 PM, John Doty <jpd AT noqsi DOT com> wrote:
>
> On Feb 12, 2013, at 10:31 PM, bsalinux AT gmail DOT com wrote:
>
> > Hello,
> >
> > Is gnetlist extractor part of gEDA?
>
> Yes. There are two gnetlist back ends for SPICE that are part of gEDA:
> "spice" and "spice-sdb". There is some pretty good documentation on
> spice-sdb at http://www.brorson.com/gEDA/SPICE/intro.html.
>
> I have an experimental SPICE back end under development at
> https://github.com/noqsi/gnet-spice-noqsi.
>
> > Are there any other extractors available?
>
> Not that I know of.
>
> >
> > I tried to do a gnucap simulation involving BS170 MOSFET and the
> > extractor did not extract / interpret four contacts for the MOSFET as
> > expected by GNUCAP.
> >
> > What was extracted was:
> >
> > M1 4 1 0 bs170
> >
> > instead of (substrate connected to source)
> >
> > M1 4 1 0 0 bs170
>
> The "spice" and "spice-sdb" back ends assume that the SPICE device has the
> same number of connections as the symbol, so if you use a three terminal
> symbol, you'll get the result you're seeing. One way to get around this is
> to have the model-name attribute refer to a three terminal subcircuit in
> which the four terminal primitive device is embedded. Be sure to use a
> refdes starting with "X" in this case. Or you can use a four terminal
> symbol.
>
> My spice-noqsi back end is more flexible, with a spice-prototype attribute
> that you can attach to a symbol to give the netlister more detailed
> instructions. For the nmos-3 symbol, you could use use "spice-prototype=M?
> #D #G #S #S bs170".
>
> John Doty Noqsi Aerospace, Ltd.
> http://www.noqsi.com/
> jpd AT noqsi DOT com
>
>
>
>
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<div dir=3D"ltr"><div><div><div>Thanks John,<br><br></div><div>Would that m=
ean I should be using 4 terminal MOSFETS and join the source to substrate?<=
br></div><div>I'll try that with spice-sdb extractor.<br><br><br></div>
On GNUCAP list I was suggested to use a plugin for gnucap for gEDA.<br><br>=
</div>I just wanted to fixate my workflow so that I know what to do. I'=
m just getting my feet wet on gnucap and ngspice.<br><br></div>Thanks for y=
our suggestions.<br>
<br></div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On =
Wed, Feb 13, 2013 at 3:39 PM, John Doty <span dir=3D"ltr"><<a href=3D"ma=
ilto:jpd AT noqsi DOT com" target=3D"_blank">jpd AT noqsi DOT com</a>></span> wrote:<b=
r><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:=
1px #ccc solid;padding-left:1ex">
<div class=3D"im"><br>
On Feb 12, 2013, at 10:31 PM, <a href=3D"mailto:bsalinux AT gmail DOT com">bsalinu=
x AT gmail DOT com</a> wrote:<br>
<br>
> Hello,<br>
><br>
> Is gnetlist extractor part of gEDA?<br>
<br>
</div>Yes. There are two gnetlist back ends for SPICE that are part of gEDA=
: "spice" and "spice-sdb". There is some pretty good do=
cumentation on spice-sdb at <a href=3D"http://www.brorson.com/gEDA/SPICE/in=
tro.html" target=3D"_blank">http://www.brorson.com/gEDA/SPICE/intro.html</a=
>.<br>
<br>
I have an experimental SPICE back end under development at <a href=3D"https=
://github.com/noqsi/gnet-spice-noqsi" target=3D"_blank">https://github.com/=
noqsi/gnet-spice-noqsi</a>.<br>
<div class=3D"im"><br>
> Are there any other extractors available?<br>
<br>
</div>Not that I know of.<br>
<div class=3D"im"><br>
><br>
> I tried to do a gnucap simulation involving BS170 MOSFET and the<br>
> extractor did not extract / interpret four contacts for the MOSFET as<=
br>
> expected by GNUCAP.<br>
><br>
> What was extracted was:<br>
><br>
> M1 =A04 1 0 bs170<br>
><br>
> instead of (substrate connected to source)<br>
><br>
> M1 =A04 1 0 0 bs170<br>
<br>
</div>The "spice" and "spice-sdb" back ends assume that=
the SPICE device has the same number of connections as the symbol, so if y=
ou use a three terminal symbol, you'll get the result you're seeing=
. One way to get around this is to have the model-name attribute refer to a=
three terminal subcircuit in which the four terminal primitive device is e=
mbedded. Be sure to use a refdes starting with "X" in this case. =
Or you can use a four terminal symbol.<br>
<br>
My spice-noqsi back end is more flexible, with a spice-prototype attribute =
that you can attach to a symbol to give the netlister more detailed instruc=
tions. For the nmos-3 symbol, you could use use "spice-prototype=3DM? =
#D #G #S #S bs170".<br>
<br>
John Doty =A0 =A0 =A0 =A0 =A0 =A0 =A0Noqsi Aerospace, Ltd.<br>
<a href=3D"http://www.noqsi.com/" target=3D"_blank">http://www.noqsi.com/</=
a><br>
<a href=3D"mailto:jpd AT noqsi DOT com">jpd AT noqsi DOT com</a><br>
<br>
<br>
<br>
</blockquote></div><br></div>
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