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Simulators >> RF Simulators >> PSS: Difference between writepss/readpss and writefinal/readic
https://designers-guide.org/forum/YaBB.pl?num=1233595746

Message started by Niklas on Feb 2^nd, 2009, 9:29am

Title: PSS: Difference between writepss/readpss and writefinal/readic
Post by Niklas on Feb 2^nd, 2009, 9:29am

When using PSS analysis one can set the writepss/readpss and writefinal/readic options respectively, to save the steady state conditions and use them as an initial condition for the next simulation. From the Spectre documentation I don't really get what the difference between both methods is. Is one method superior to the other or is there any rule under which simulation conditions one should use one method or the other?

Best regards
Niklas

Title: Re: PSS: Difference between writepss/readpss and writefinal/readic
Post by Andrew Beckett on Feb 3^rd, 2009, 10:09pm

writepss/readpss captures the final steady-state solution, both for shooting and (since recent MMSIM701 ISRs and MMSIM71), harmonic balance. This represents the entire solution - the whole period. Using writefinal/readic only captures the final DC operating point (and reuses it).

Using writefinal/readic means that it still needs to solve from scratch; it's just that the DC for the steady-state may be closer to the final settled value. With writepss/readpss it should be very close to the final solution (it still needs to solve, because the circuit conditions may have changed a little in the meantime, between the run with writepss and the run with readpss).

Does that help?

Regards,

Andrew.

Title: Re: PSS: Difference between writepss/readpss and writefinal/readic
Post by Niklas on Feb 3^rd, 2009, 11:49pm

OK, now I got it. Thank you for your help!
Unfortunately, with respect to simulator options the Cadence documentation is often very indefinite :-(

Regards,
Niklas