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Simulators >> Timing Simulators >> XA gives inaccurate currents!
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Message started by topquark on Apr 20th, 2011, 2:11am

Title: XA gives inaccurate currents!
Post by topquark on Apr 20th, 2011, 2:11am

Hi folks,
HAve any of you experienced this?
XA (sim level 4 or even 6- SPICE-like) gives highly inaccurate current measurements in simulations.
Ok, to be specific I'm simulating a Charge Pump which is a switching cap circuit. While level 4 gives reasonably fast and correct voltage waves (<5% error) to ensure functionality, current measures have let me down  >:(

Does anyone know why this is the case and any work arounds?
I'm trusting hspice or Spectre current measures at the moment which take a long time to run.
Synopsys have no documentation regarding this beahviour.

Appreciate your views.
Cheers,
Topquark

Title: Re: XA gives inaccurate currents!
Post by John O Donovan on Apr 21st, 2011, 9:28am


Hi,

Someone else may answer the XA question, but if you have access to Spectre already and it is a recent version (7.2 or 10.1) then have you tried using the +aps option to enable APS.

Regards,
 John

Title: Re: XA gives inaccurate currents!
Post by topquark on Apr 26th, 2011, 2:49am

Sorry, guys.
it was more of a rant than a genuine issue  :P

I confirmed the current values with both APS and XA - they were quite high due to some circuit issue, not simulator!
Now, I've fixed it but a word of caution when using XA - always use level 4 or above to get trustworthy current numbers!

Cheers,
topquark

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