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Electronics => FPGA => Topic started by: matrixofdynamism on June 21, 2022, 11:51:12 pm

Title: Using SPICE for signal integrity simulation
Post by: matrixofdynamism on June 21, 2022, 11:51:12 pm
Signal integrity simulation programs like HyperLynx, ANSI Wave SI, Sigrity e.t.c are robust but very expensive. Ultimately they carry out simulation of a system containing transmission line models connected to models of IO buffers. The IO buffer models could be IBIS or SPICE models.

I am wondering, why spend so much money on such expensive programs? Can't we just create the entire scenario we want to simulate in free SPICE program like LT SPICE and just run the simulation in that instead?
Title: Re: Using SPICE for signal integrity simulation
Post by: asmi on June 22, 2022, 02:17:58 am
No vendor is going to release a SPICE model of their IO structures because they reveal their internal structure. So IBIS/HSPICE model is the best you ever going to get.
As far as simulation goes, some simulation tools is included into relatively (compared to tools you've mentioned) affordable eCADs like Cadence Orcad Professional or even Standard editions (though the latter is pretty limited because it can't run post-route PCB sims, only pre-route "model" ones). Altium Designer presumably also contains SI simulation tool, but I'm yet to figure out how to use them, and so I use my old license of Orcad Pro whenever I need to run board-level sims.
Title: Re: Using SPICE for signal integrity simulation
Post by: matrixofdynamism on June 23, 2022, 09:03:15 am
About Altium I have been told that the jack of all trades is master of none, so Altium designer may have a lot of simulation capability but it is not reliable. This is heresay though.
Title: Re: Using SPICE for signal integrity simulation
Post by: tggzzz on June 23, 2022, 09:23:30 am
Have a look at Micro-Cap, which is now free as in beer.

I believe it can import IBIS models, but I haven't tried it
Title: Re: Using SPICE for signal integrity simulation
Post by: KaneTW on June 23, 2022, 10:22:50 am
Same, haven't figured out how to use Altium's SI analysis yet. Evaluating HyperLynx rn and it's night and day.
Title: Re: Using SPICE for signal integrity simulation
Post by: Bassman59 on June 23, 2022, 06:14:14 pm
Same, haven't figured out how to use Altium's SI analysis yet. Evaluating HyperLynx rn and it's night and day.

Which is better? Saying "it's night and day" doesn't make that clear.
Title: Re: Using SPICE for signal integrity simulation
Post by: SiliconWizard on June 23, 2022, 06:23:57 pm
Have a look at Micro-Cap, which is now free as in beer.

I believe it can import IBIS models, but I haven't tried it

Yup, IBIS is supported. I haven't tried it yet either, but look at the documentation, it seems fully documented.

I do like Micro-Cap quite a bit. Too bad it's become abandonware (but good thing they released it for free.)
Title: Re: Using SPICE for signal integrity simulation
Post by: KaneTW on June 24, 2022, 01:04:09 am
Same, haven't figured out how to use Altium's SI analysis yet. Evaluating HyperLynx rn and it's night and day.

Which is better? Saying "it's night and day" doesn't make that clear.

Sorry. Hyperlynx is way better and easier to use/configure.