Assura Question-Cap Extraction

[George]

Dear all,
I am using Assura to carry out extraction.
In the 'Extraction' form, there is an option called 'Cap Extraction Mode'
and we can choose 'coupled' or 'decoupled'.
My question is what is the difference? I have read the manual, but i still
not understand. How to conside the choice? Also, it said it will extracted
the capacitance on SELECTED net, but how to select? It seem that there is no
selection required.
Before using Assura, i was using Diva and i only need to choose 'Cap ALL'
then. So, i would like to share your experience on Assura.

Thank you very much!

Best Regards,
Raymond

 

[Andrew Beckett]

Raymond,

Decoupled will take any capacitance between different nets and
decouple it so that all capacitors are to ground. Obviously this is
less accurate, but results in a smaller network and can be fine for
simple modelling. Coupled keeps the capacitors between nets so that
they are output between those nets (although if you specify a minimum
capacitor value, smaller capacitors get decoupled and then summed up,
and then filtered out if the total decoupled sum is less than the
minimum).

If you're choosing to extract the capacitance of selected nets, you
can (in Assura 3.1) pick the nets from the schematic which it will
extract. There's something on the form which shows that (I'm running
Windows at the moment so can't quickly remind myself what the form
looks like - to be honest the form is completely different depending
on which Assura version you're running).

There's far more flexibility with Assura RCX than Diva, which is why
you have more choices.

Regards,

Andrew.

On Fri, 24 Sep 2004 13:23:09 +0800, "George" <wt_cheng@yahoo.com>
wrote:

Dear all,
I am using Assura to carry out extraction.
In the 'Extraction' form, there is an option called 'Cap Extraction Mode'
and we can choose 'coupled' or 'decoupled'.
My question is what is the difference? I have read the manual, but i still
not understand. How to conside the choice? Also, it said it will extracted
the capacitance on SELECTED net, but how to select? It seem that there is no
selection required.
Before using Assura, i was using Diva and i only need to choose 'Cap ALL'
then. So, i would like to share your experience on Assura.

Thank you very much!

Best Regards,
Raymond