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Simulators >> Circuit Simulators >> Difference between mmsim 13 and mmsim11? PDK limitation?
https://designers-guide.org/forum/YaBB.pl?num=1411378590

Message started by Jacki on Sep 22^nd, 2014, 2:36am

Title: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by Jacki on Sep 22^nd, 2014, 2:36am

Hello,

I am doing transient simulation of my design with ic 6.16, mmsim 13. But sometimes I get the errors as shown below. When I change to mmsim 11, for the same simulation, I don't have any error reports.
I do set 64 bit binary when I am using mmsim 13.
My question is if there is any special setup I should do when I am using mmsim 13? Is it possible that the design kits from the foundry don't support mmsim 13? What could cause the problem?

Error found by spectre during initial setup.
ERROR (CMI-2049): I0.I0.I33.C0.r11 of esdndsx: Value of `weff' should be greater than zero.
ERROR (CMI-2049): I0.I0.I50.C0.r11 of esdndsx: Value of `weff' should be greater than zero.
ERROR (CMI-2049): I0.I0.I42.C0.r11 of esdndsx: Value of `weff' should be greater than zero.
.....................................................

Appreciate if experienced people can help.
Thank you.
-Jacki

Title: Re: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by boe on Sep 22^nd, 2014, 5:43am

Jacki,
you give very little information, so we can only guess.
Many years ago, I had a similar effect between Spectre & AMS, caused by a string in the netlist where a number was needed. One tool would read "10" as 10, the other as some strange value....
- B O E

Title: Re: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by Jacki on Sep 22^nd, 2014, 9:29am

boe wrote on Sep 22^nd, 2014, 5:43am:

Hello B O E,

Thank you for your reply. I want to give more information, but I don't know where the problem is, so I cannot provide more information, and just ask generally. I think the problem only happens when I add the IOPADs / Digital cells from CORELib in the design kits.
- Jacki

Title: Re: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by Geoffrey_Coram on Sep 23^rd, 2014, 2:32pm

I think boe was suggesting that you show the netlist, particularly an example line involving esdndsx.

Title: Re: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by boe on Sep 24^th, 2014, 2:17am

Jacki wrote on Sep 22^nd, 2014, 2:36am:

... My question is if there is any special setup I should do when I am using mmsim 13? Is it possible that the design kits from the foundry don't support mmsim 13? ...

That should not be necessary. A design kit and models that work with MMSIM 11 should also work with MMSIM 13.
The behavior you describe is IMO probably a bug - be it in the simulator, the models or the design kit.
- B O E

Title: Re: Difference between mmsim 13 and mmsim11? PDK limitation?
Post by Jacki on Oct 10^th, 2014, 5:47am

Hello B O E and Geoffrey_Coram,

Thank you for your comments. I heard somebody had the quite similar problem with the early version of mmsim 13, but when they changed to the later version of mmsim 13, then everything was fine.
-Jacki