C3 interconnect delay in Slow corner is larger than Fast corner ?

[gNATO]

18.0.1 Pro & Stratix 10

One of my failed setup timing path has larger -ve slack in Fast Corner than Slow Corner. When look deeper, I noticed the C3 interconnect delay in fast corner is much larger than in slow corner as shown in the attached diagram. Any idea ?

Thanks

[IDeyn]

Hi gNATO!

I can't see all the diagram, and to answer your question it is an addititional information need to be added.

You can see that it is not only C3 interconnect that is larger for a Fast Corner, also practically all delays are larger (LAB RE, C4 inerconnect, R2 interconnect and so on).

For now I can say that maybe it is an effect called late derating in On-Chip Variation mode of analysis.

It can be even Stage-based OCV, where some part of path can behave in another way as it should be expected.

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Best regards,

Ivan