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Other CAD Tools >> Physical Verification, Extraction and Analysis >> Problem in RCx assura extraction
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Message started by turturri on Jul 21^st, 2005, 11:35am

Title: Problem in RCx assura extraction
Post by turturri on Jul 21^st, 2005, 11:35am

i am using a 0.18 um IBMprocess for a multiGHz circuit. I have a clean DRC and LVS. But when i perform extarction using assura, and simulat I have absurd results. Also the sum of R is shown as NA while the individual resistances are being tabulated. I am using multi finger transistors and each finger seems to be providing 2-3 ohms and these r supposedly adding up which is weird.

ne suggestions would be very helpful. am i missing ne switch or option that i should chose. coz only C extraction seems to be working fine.

thanx

Title: Re: Problem in RCx assura extraction
Post by Andrew Beckett on Jul 31^st, 2005, 9:54pm

If you're using recent versions (I don't remember whether it was IC5033 or IC5141 when this came in; IC5141 I think), then the parasitic backannotation and reporting in the "MSPS" tool has changed so that you need to do a DC simulation in order to see the resistor values. Previously it used to just add up all the resistors and display that, which was quite frankly wrong.

You say your simulation results are absurd - unfortunately I can't help you with that without more details.

I suggest you read the documentation on the MSPS stuff carefully. I think (can't check right now) it's at:

<instdir>/doc/parasim/paramsim.pdf

Regards,

Andrew.