max transition and max load

[manikanta.9332]

Hi all,

max transision and max load are equal are not?

Thanks..........

 

[rca]

What do you mean equal?
Transition, is the time needed to the signal to goes to zero to one or one to zero.
Load, is the capacitance seems by the output pin of the std cell.
Both are used in the liberty to characterize the timing, and the maximum constraint should not be violated, because the timing will be extrapolate, and we don't know if the value will be optimist or pessimist.

 

[manikanta.9332]

Hi all,

Sorry max fanout and max load are equal are not ?

Thanks........

 

[yadavvlsi]

Max fanout limit is defined to avoid max. cap and max. transition violations as far as you meeting them, you can ignore max. fanout violations up to a limit. But if fanout is more than 32 (not a hard bound), your effective load can increase because of miller effect.
https://en.wikipedia.org/wiki/Miller_effect