Nazgul,

 One note, ICXYX is the environment version number and
unrelated to the simulator version. Spectre RF is in the MMSIM
release stream.

  Here some ideas to try:

1) You could try Harmonic Balance and see what the results are

2) Starting with a sine wave to test the circuit, does it reach
  steady state by the end of the transient simulation?
  if the transient simulation has not settled then allowing more time
  to settle may resolve the issue

3) If you tighten the transient tolerances do the result match the
   PSS results better?

                                                                           Sheldon

SpectreRF is simply part of Spectre. To find out Spectre's version, use 'spectre -h', or 'spectre -V' or 'spectre -W'.

Many people cause problems for themselves by using absurdly tight tolerance settings. If you are using absurdly tight tolerance settings, stop. If you are not, and PSS does not converge despite using a reasonable tstab, then your circuit might not be periodic.

If it is a driven circuit, use strobing at the clock frequency and perform a long transient analysis. If the strobed waveforms become constant valued, then your circuit is periodic and SpectreRF should work. Use the settling time to determine a reasonable value of tstab. If they do not become constant valued, then you need to determine why your circuit is not periodic. I recommend that you observe the power supply currents when running this test.

-Ken

Hi Ken,

Thank you for the reply..
The reason why I went with tight tolerances was, at normal tolerances my PSS results were not matching with transient results. I thought slightly tightening my tolerances will help me, but that didn't help me either.
During the normal transient I can see that my circuit is periodic, But the output is not a proper sine wave. Its slightly irregular with lot of higher harmonics, but its periodic.

regards,
nazgul