What is the difference between ".dspf" and ".sdf"?

wat is the difference between ".dspf" and ".sdf"?

wat is the difference is results obtained by analyzing the design using each of them?

STA doubt

sdf - contains delays for every gate and net in the design
dspf - contains RC parasitics data on every net segment in the design.

Re: STA doubt

thank you very much

can u let me know the difference in results that we get when we use each of them for STA

and

normally which format (b/w the both files) should be used for back-annotation.

kindly reply me

Re: STA doubt

Sorry , I didnt use any other STA tools. All below information regarding Synopsys Prime time.

1) In PT, SDF is the high precedence for Annotation compared to aby other information. So, if you annotate SDF, Interconnect delays ,R's and C's from DSPF will not be used for calculatiing the pin-to-pin delays. What ever the info SDF contains, PT ALWAYS use the annotate capacitance to calculate the transition times, since SDF doesnt contain transition information. if there are no annotated parasitics, PT will use cap information derived from WLM to calc transition time.
2)Its overhead of reading the DSPF . It doesnt make sense to annotate the DSPF on a design, which is already has SDF applied to it. Insted read set_load file for parasitics. This will generally having cap and transition times, which are more pesimistic than derived using DSPF, but read time will be much faster...


Regards,
Sam