Why we have to close timing at multi corners?

[kirangu]

During sign off analysis, we have to close timing at different corners like best, worst or typical. Why we have to do that?

 

[huckle]

A chip typically is operated at different P, V, T conditions.
The different conditions can change the delays in the circuit so closing it in one corner (ie. PVT condition) doesnot ensure its operation in another corner.
We can't know until we analyze it in the extreme corners.
The corners are chosen to represent the worst, best and typical operating condition for the chip.
All chips are different in their selection of worst, best and typical operating condition - somewhat technology dependent and also dependent on application of the chip.

 

[lostinxlation]

because manufacturing of silicon is not perfect and has some variations of which the fast and slow corners are both end.

 

[jeevan.life]

A chip typically is operated at different P, V, T conditions.
The different conditions can change the delays in the circuit so closing it in one corner (ie. PVT condition) doesnot ensure its operation in another corner.
We can't know until we analyze it in the extreme corners.
The corners are chosen to represent the worst, best and typical operating condition for the chip.
All chips are different in their selection of worst, best and typical operating condition - somewhat technology dependent and also dependent on application of the chip.

Exactly, Also the wire delay vary with the varying Temperatures so it becomes important to close timing across all corners for better lifetime of the chip and to avoid functionality failures at varying conditions