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#analog-design
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# analog-design
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Eslam Morsie
07/26/2021, 11:37 AMIs there anyone here tried to make corners simulation using the command 'altermod' in ngspice?
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Tim Edwards
07/26/2021, 12:49 PMThat would be a really roundabout way of doing a corner simulation. Why do that instead of using the corner simulation models directly?
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Eslam Morsie
07/26/2021, 12:51 PMI want to run more than one corner in the same run, I found in the manual that altermod command do that but I didn't figure out how to do that.
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Tim Edwards
07/26/2021, 12:51 PMMy advice is not to do multiple corners in one run.
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Amro Tork
07/26/2021, 1:25 PM@Tim Edwards I wanted to ask you about this why not? Using such technique usually speeds up the simulation. Because it doesn't have to rebuild the circuit in memory only loading models.
@Eslam Morsie I think let's follow @Tim Edwards advise for now.
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Eslam Morsie
07/26/2021, 1:26 PMok
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Tim Edwards
07/26/2021, 1:27 PM@Amro Tork: Ideally, yes, but in practice it's just a pain to work with ngspice's built-in command language, and it makes everything unportable (e.g., to xyce).
Once upon a time, the tclspice version of ngspice worked really well for those kind of things, but it has been broken for years.
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Amro Tork
07/26/2021, 1:29 PM@Tim Edwards I used to do that with most of commercial tools: ELDO, Spectre, HSPICE, etc...
@Tim Edwards I understand that whatever @Eslam Morsie doing is not going to be portable to other tool like Xyce. But is there any limitations in the model cards files that I should look out for?
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Tim Edwards
07/26/2021, 2:56 PM@Amro Tork: As far as I'm aware, there are no particular issues currently for running with ngspice other than the fact that a lot of the models are binned over narrow L and W ranges and are not at all well characterized outside of those ranges.
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Amro Tork
07/26/2021, 6:20 PM@Tim Edwards Thanks for all the help.
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