DC analysis

When I do a DC analysis and click annotate DC Operating Points it
displays "id, vgs and vds". I would like it to include "vdsat" as well,
how can I do that?

Thanks

 

edit CDF of MOS cell, add vdsat to opPointLabelSet and
make sure the symbol includes a label for displaying
the value such as cdsParam(n).
hope it'll work.
stephane

 

Also what does each "region" correspond to in the dc operating point
parameter. i.e. region=1,2,..

Thanks

 

according to spectre -h bsim3v3

Estimated operating region. Spectre outputs number (0-4) in a rawfile.
Possible values are off, triode, sat, subth, or breakdown.

that would mean 0=off, 1=triode, 2=sat, 3=subth & 4=brdwn

stephane

 

If you do not have write permission to the instance, you can change any
parameter from Edit->Component Display Menu in the schematic window
after a succesful simulation.
check box of parameter in select label
select operation point in parameter labels.
change one of the parameter.

Ercan

 

Is there a limit on the number of transistor parameters you can
display? Because for pmos I have id, vgs, vth, vds and vdsat and all
of them are displayed, however for nmos vdsat is not displayed. Is
there any way around it?

Thanks

 

On the symbol, you need to have cdsParam(n) labels - each of which are
"ILLabel" type. The n would be from 1 to 5 in your case. The idea is that each
is a SKILL function which evaluates to display the 1st, 2nd, 3rd (etc)
parameter in the list.

If you don't have a label on the symbol, it can't be displayed...

Regards,

Andrew.

 

How would you recomend library users to provide themselves with symbols
with more cdsParam(n) than in the provided library?

Example: In the standard analogLib there is mostly 3 cdsParam entries
per symbol. I need to have administrator rights to be able to set the
base CDF for a particular symbol. If I take my time to do this, then the
next release of the library will be back to standard, and I will have to
start all over again.

We have some symbols in-house that I sometimes add a couple of ILLabels
on. These are always added to the effective CDF and are lost on the next
icfb session. If I could save my modifications in a file that are
reloaded on the next session it would be a great help because I don't
need to keep a personal copy of company wide symbols. (Which is a bad
thing as other users would like to be able to use my schematics)

Kind regards,

 

One thing you could do is to write some SKILL to add these labels to the
symbols, and do it in "scratch" mode. i.e. open the symbols as follows:

cv=dbOpenCellViewByType("analogLib" "nfet" "symbol" "schematicSymbol" "s")

Then you can make the change in VM only.

Alternatively you could build your own analogLib from our analogLib. This is
probably what I'd do, and I'd make sure that I did it using SKILL, so that I
could re-create the analogLib when a new release came along with the minimum
of fuss.

You could also contact customer support and ask us to put a couple more labels
on each of the devices - I doubt whether any more than (say) 5 would be used
by most people?

Regards,

Andrew.