I am simulating PSS+Pnoise on my LC oscillator for jc and jcc jitter measurement. From the phase noise plot I got positive value at low frequency offset, which I think makes the jitter calculation incorrect. I searched and read through some old threads with the same topic. It seems this issue is connected to the MMSIM version, but nobody clarified it. I am likely working with IC61+MMSIM60, although I need to check with the server manager. So is it the case that if I upgrade MMSIM, this issue "positive phase noise" can be solved? Or is there anything else I am missing? Thanks in advance.
This is discussed in Cadence Online Support article 1832229.
Here is the complete link:
Starting around MMSIM 7.2, there is a parameter called "lorentzian". This parameter determines if the Lorentzian plot is used in the oscillator noise analysis. If you want to plot phase noise without the "non physical" results, select lorentzian=yes in the pnoise options.
You really need to be using MMSIM12.1.1 or 13.1 latest ISRs. You're using a simulator version that is 5+ years old and no longer supported. Please have your system administrator download the latest ISR from http://downloads.cadence.com .