I want to know where to use sdf and spf.

[Austin_Bae]

Both spef and sdf can be used for PrimeTime, but I know that spef is preferred.

However, I don't know why sdf is preferred when doing Dynamic Timing Analysis.

Isn't it SPEF that R and C values are added in the sdf file?
So I think SPEF is more accurate, but it's confusing.

 

[ThisIsNotSam]

SDF, typically, appears early in the design flow. We can do simulations of a gate level netlist with an SDF and check if things are ok.
SPEF appears much later since it is the output of extraction done on a layout. At this point, you rarely care about design simulation since you will do LEC between final layout and netlist. In a sense, yes, SPEF is more accurate, but it also is meant for a very different use.

 

[Austin_Bae]

SDF, typically, appears early in the design flow. We can do simulations of a gate level netlist with an SDF and check if things are ok.
SPEF appears much later since it is the output of extraction done on a layout. At this point, you rarely care about design simulation since you will do LEC between final layout and netlist. In a sense, yes, SPEF is more accurate, but it also is meant for a very different use.

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