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sivacharan Junior Member Offline Posts: 19	node capacitance Dec 18^th, 2006, 8:17pm If i want to see the total capacitance occuring at a particular node, which simulation will be useful in spectreRF?? Thank you.
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Ken Kundert

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Re: node capacitance
Reply #1 - Dec 18^th, 2006, 10:22pm

If you are running standalone you would run an info analysis ...
Quote:

printCapacitanceTable info what=captab

If you are running in Artist, you might be able to specify that this through the Artist UI, but I am not familiar with how you would do that. Alternatively, you can put that statement in a file and tell Artist to include it in the netlist.

-Ken

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ACWWong Community Fellow Offline Posts: 539 Oxford, UK	Re: node capacitance Reply #2 - Dec 19^th, 2006, 2:53am In artistADE, you can tick the captab button in choose analyses->dc->options or choose analyses->tran->options. In DC you get the node capacitances calcualted from the dc op point. in tran you can get the node capacitances at different time points using "infotimes"
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sivacharan Junior Member Offline Posts: 19	Re: node capacitance Reply #3 - Dec 19^th, 2006, 11:14pm when i see the dc operating point of an nmos or pmos, the spectre tool is showing the -ve capacitance for cgs and cds ...etc. what does it mean?? thank you.
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ACWWong

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Re: node capacitance
Reply #4 - Dec 20^th, 2006, 3:23am

sivacharan wrote on Dec 19^th, 2006, 11:14pm:

when i see the dc operating point of an nmos or pmos, the spectre tool is showing the -ve capacitance for cgs and cds ...etc.
what does it mean??

See the following relevant post.
http://www.designers-guide.org/Forum/YaBB.pl?num=1160834621
Please bear in mind that the dc-opertaing points for any transistor are model parameters, whereas as captab gives total capacitance on nodes/nets in a circuit.

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