Low power design timing closure

[rahul.achates]

Hi

In low power design, there are possibility that different blocks running at different power supply. In that case how STA tool take care of timing closure ?

Does STA tool understand UPF file , even if tool understand then do we need to provide mora than one timing lib or SPEF ?

suppose my design has 2 blocks , one is running at 1 v and other block is running at 1.2 v ..

then during STA, do I need to provide 1.2V .LIB and 1v .LIB ??


or do I need to close timing at 1V and 1.2 V separately .. it means all blocks should word at 1v (even 1.2V block too ) and 1.2V ??


I am confused here ... you may give answer that we can use MC mode .. where we can give all corners related information to the tool and then tool will run all corner one by one ... this save some time but my question will still there ... how does STA tool knows at what voltage a particular block is running ? and how much tolerance should be there for voltage ?


Regards
Rahul

 

[rca]

Yes you need to define a library file for each power corner.
in PrimeTime, you could indicate this sub-design used this library, and then you could execute your STA.
UPF is the script to handle this also. And generally you should have already used a UPF/CPF file during the synthesis and the PnR.