Question on Cadence Capacitor Output Templates

What is the meaning of cbdbi, cbsbi, bddbi, cgdbi, cggbi, cgsbi and cssbi? The cadence manual doesn't provide any information about them. I need an accurate capacitor model for simulation, but was confused with them. Can anybody help me explain the meanings of them? Thanks!

As outlined in the Forum Guidelines, please do not post the same question in multiple forums.

These are operating point parameters for the bsim3v3 model, and are documented in the Virtuoso Simulator Components and Device Models Reference manual <MMSIMinstDir>/doc/spectremod/spectremod.pdf . You can also find out about them by typing "spectre -h bsim3v3". They are:

71      cddbi (F)         Intrinsic drain capacitance.                                                                                           
72      cssbi (F)         Intrinsic source capacitance.                                                                                          
73      cggbi (F)         Intrinsic gate capacitance.                                                                                            
74      cgsbi (F)         Intrinsic gate-to-source capacitance.                                                                                  
75      cgdbi (F)         Intrinsic gate-to-drain capacitance.                                                                                   
76      cbdbi (F)         Intrinsic bulk-to-drain capacitance.                                                                                   
77      cbsbi (F)         Intrinsic bulk-to-source capacitance.                 

Unfortunately there is not really more detailed information on them. We recently went through the process of adding in cross-references in the bsim4 documentation from the operating point output parameters to the appropriate equations, but that hasn't happened for bsim3v3 yet. If you want that, please contact customer support to help us prioritize it for the older bsim3v3 model. You may also be able to find some useful information at the Berkeley bsim site.

Regards,

Andrew.

 These are the DC operating point parameters for
the intrinsic capacitances of the Bsim3v3 MOS model
(Spectre implementation).

Do a 'spectre -h bsim3v3' from the command line:

71      cddbi (F)         Intrinsic drain capacitance.
72      cssbi (F)         Intrinsic source capacitance.
73      cggbi (F)         Intrinsic gate capacitance.
74      cgsbi (F)         Intrinsic gate-to-source capacitance.
75      cgdbi (F)         Intrinsic gate-to-drain capacitance.
76      cbdbi (F)         Intrinsic bulk-to-drain capacitance.
77      cbsbi (F)         Intrinsic bulk-to-source capacitance.

Or have a look at the
'Virtuoso Simulator Circuit Components and Device Models Manual,
BSIM3v3 Level-11 Model (bsim3v3)'.

The are well documented.

Bernd

Thanks for your reply, Andrew. What is the difference between CGG, CGGBI, CGGBO? I cannot find their definitions from the manual and am not able to interprate their physical meanings. In the Figure I provided, I notice that  CBSBI = 80.8f while CBS is only 0.448f. If xxxBI is defined to be the intrinsic capacitance, why is it larger than the non-intrinsic conuterpart? Can you provide some more detailed information?  

BTW: I initially posted the question in the analog SKILL forum. Later I found the analog design forum is more approprite for this question and posted it here, but forgot to delete the old message.  Anyway, I would like to thanks for your remind.  

cggbo is the intrinsic capacitance for bsim4, not bsim3v3 - so it's not relevant here. cgg is a partial derivative so it's not directly comparable - the intrinsic capacitances are (I believe) the capacitances independently of the operating point - but I'm not 100% sure from a quick glance (I'm a bit pushed for time today).

I suggest you contact customer support.

Regards,

Andrew.