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Simulators >> Circuit Simulators >> Spectre diiference in reltol?
https://designers-guide.org/forum/YaBB.pl?num=1211791608

Message started by bernd on May 26^th, 2008, 1:46am

Title: Spectre diiference in reltol?
Post by bernd on May 26^th, 2008, 1:46am

Hi,

This is a specific tool question about Cadence Spectre in the
Analog Environment, but maybe some of the Gurus here have
seen this and know an explanation.

I discovered a strange thing.
In Spectre I always see that the value of reltol reported in the
spectre.out file is 1 decimal power smaller than the
specified reltol value in the simulation options.

Is there any explanation for this behaviour?
And which is the reltol value the simulator is using?

Thanks in advance,
Bern d

Title: Re: Spectre diiference in reltol?
Post by byang on May 26^th, 2008, 8:07am

Hi, Bernd,

This is caused by errpreset=conservative. When errpreset=conservative in a tran statement, the used reltol in that tran analysis will be equal to 0.1 * the reltol specified in options.

When errpreset=liberal or moderate, the reltol doesn't change.

byang
http://www.gemini-da.com

Title: Re: Spectre diiference in reltol?
Post by bernd on May 26^th, 2008, 8:49am

Thanks ;)