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Simulators >> Circuit Simulators >> how to deal with this simulation error?
https://designers-guide.org/forum/YaBB.pl?num=1147057438

Message started by jaylin79 on May 7^th, 2006, 8:03pm

Title: how to deal with this simulation error?
Post by jaylin79 on May 7^th, 2006, 8:03pm

Hi guys,

Can you help me to deal with this simulation error, I use Hspice to simulate. all the warning and error are following:

**warning** effective csat(is) = 100.0000m is too large in diode 0:d2

**warning** effective csat(is) = 100.0000m is too large in diode 0:d3

**warning** rs for 1:d3 limited to 1.000E-05

**warning** mosfet device 1:m1 cdsat is too small at temperature 25.000
value= 1.00000E-32,cdsat reset to epsmin

**warning** mosfet device 1:m1 cssat is too small at temperature 25.000
value= 1.00000E-32,cssat reset to epsmin

**warning** conductance of 0. on node 1:5 iter= 12

**diagnostic** rebuilding matrix with pivot option

**diagnostic** rebuilding matrix without pivot option

**diagnostic** dc convergence failure,
resetting dcon option to 1 and retrying

**diagnostic** dc convergence failure,
resetting dcon option to 2 and retrying.

no convergence with standard algorithm, trying damped pseudo-transient

*** initial damped pseudo transient completed. ***
*** final try started ***

**warning** This was a difficult operating point.
You can speed up your simulation by specifying:
.OPTION CONVERGE=1
**error** internal timestep too small in transient analysis

time = 5.36237E-09; delta = 1.90735E-15; numnit = 335

Best Regards
Jay

Title: Re: how to deal with this simulation error?
Post by Geoffrey_Coram on May 16^th, 2006, 7:17am

Strange model for the diode, if the satuation current is 0.1 Amp. Are you sure this is right? Is it a really big device?

I'd suggest sorting out the model warnings before worrying about the simulation failure.

Also, you might want to look at the operating point that it finally does find to make sure it is reasonable.

Title: Re: how to deal with this simulation error?
Post by mikki33 on May 28^th, 2006, 10:05am

I would suggest check the dimention of the diodes. If you have m^2, it may explain many things...

If all is OK, try to use PWL for you supply. Start with the 0 and gradually rise it to the VDD voltage.