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piao
Joined: 12 Feb 2003
Posts: 223
Helped: 7
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 28 Jul 2004 14:51 a question about Hspice simulation |
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Hi,
I have a question during Hspice simulation. I use .ic statement to set the value of the initial operating point, and in TRAN statement UIC options.
In Hspice user manual, it is said that if we use .OPTIONS OFF it will set all the nodes not set by .ic and .nodeset to 0.
However, during simulation, I found whatever the voltage I set to the node, if I use .OPTIONS OFF , this node will drop quickly to 0 with step I set in the TRAN statement. I am not sure what happens.
Who can help me to explain it? Thanks in advance.
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shiowjyh
Joined: 29 May 2003
Posts: 114
Helped: 1
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| 29 Jul 2004 3:27 Re: a question about Hspice simulation |
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Have you suffer from convergence problem??
Try to use a ramp power instead, if you did have issue on it.
The insertion of initial condition is speed up your simulation time(initial DC operating point is not calculated) or get rid of convergence problem in some cases...
For a regular simulation, we hardly set any .ic or .nodeset or .options off... unless the convergence problem comes out.
Q:
1. Are you sure of the setting .ic is correct if option OFF is not apply?
2. It is ok on 2003.09 I tried, which version you are using?
Regards,
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piao
Joined: 12 Feb 2003
Posts: 223
Helped: 7
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| 21 Aug 2004 6:39 a question about Hspice simulation |
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I did have convergence problem.
And I use a ramp power instead. what you mean is I need not use the .ic statement is I use a ramp power?
I am sure of the setting .ic is correct. and version is 2001.
So I am not sure how to solve the convergence problem in such situation.
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shiowjyh
Joined: 29 May 2003
Posts: 114
Helped: 1
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| 23 Aug 2004 8:47 Re: a question about Hspice simulation |
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Please have your time to read over the contents in following link, and hope this can help you to solve convergence problem...
http://www.edaboard.com/ftopic50886.html
Regards,
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