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Peak and average IR drop analysis mode

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Hello,

I am not sure about what means peak and average IR drop mode analysis in Encounter. What of these two analysis modes should be considered for power plan optimization?

I have a small block design (5K gates) operating at very low frequency (640 KHz) and there is a big difference between the results of these two analysis modes:

  • worst IR drop average analysis: 9.8035e-05 v

  • worst IR drop peak analysis: 4.3088e-01 v

Is average analysis frequency dependent? But voltage drop is not event dependent and so can cause timing problems also at low frequencies?

Thanks in advance.

 


Originally posted in cdnusers.org by clsantos
Parents

  • Hello,

    Considering your answers and information found in this article (http://www.soccentral.com/results.asp?CategoryID=488&EntryID=19453)
    I think these different analysis modes should be used for:
    Optimize power rings/stripes: Average/static analysis;
    Insert DECAP cells or avoid that all logic switch at the same time: Peak/dynamic analysis.

    However, concerning elvis' answer, if FE's peak IR drop analysis does not consider C effect thus the natural decoupling capacitance of power network is not considered. Besides that, this analysis will not take into account inserted DECAP cells. Are these assumptions correct?
    So, what is the purpose of this FE's peak analysis?


    Originally posted in cdnusers.org by clsantos
Reply

  • Hello,

    Considering your answers and information found in this article (http://www.soccentral.com/results.asp?CategoryID=488&EntryID=19453)
    I think these different analysis modes should be used for:
    Optimize power rings/stripes: Average/static analysis;
    Insert DECAP cells or avoid that all logic switch at the same time: Peak/dynamic analysis.

    However, concerning elvis' answer, if FE's peak IR drop analysis does not consider C effect thus the natural decoupling capacitance of power network is not considered. Besides that, this analysis will not take into account inserted DECAP cells. Are these assumptions correct?
    So, what is the purpose of this FE's peak analysis?


    Originally posted in cdnusers.org by clsantos
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