Assura QRC capacitor coupling mode

[emont89]

Hi all,

I have a question about the Extraction tab of the Assura QRC editor. In the section "cap coupling mode" it is possible to switch between Coupled, Decoupled or Decoupled to Substrate . Which is the difference between these options and, above all, in which kind of parasitic simulation it is recommended to use an extraction with coupled or decoupled or decoupled to substrate coupling mode?

Thanks

 

[erikl]

AFAIR Coupled means extracting all C's (incl. extracted RC's) capacitances between all nodes (incl. substrate), Decoupled means extracting capacitances between all nodes to substrate only, and Decoupled to Substrate extracting all C's between all nodes apart from substrate.

Which option you select depends on your needs, of course:
Coupled for sure generates a very large data base. If you fear coupling of signals between individual nodes, select Decoupled to Substrate, if RC coupling to GND, i.e. bandwidth limitation by additional poles is your problem, choose the Decoupled option.

 

[emont89]

Ok, thank you for the reply! So the Coupled option is the most complete one, if the database is not too big this is the most correct choice I suppose.

 

[erikl]

You're right! But also postLayout simulation will take longer.

 

[emont89]

OK! Thanks a lot, now it is more clear!