Dear all,

when simulating the phase noise of an oscillator + CMOS buffer it turns out that the wideband phase noise is dominated by contributions of the CMOS buffer. The simulator returns a phase noise floor of -160dBc/Hz (broadband noise). Can the simulator be trusted to resolve such low levels accurately (assuming accurate device models)?

I would say yes, but I would like to hear if someone thinks otherwise. The reason for asking is a discrepancy between measurements and simulations. Assuming a phase noise floor of -150dBc/Hz would lead to agreement between measurements and simulations.
Personally, I think 10dB is a huge difference so I don't think simulator inaccuracy is a likely cause...

Regards

Peter

Dear ACWong,

yes, power and frequency are correct.
I also ran simulations on an extracted netlist, including bondpad/package parasitics + noise from the biasing.

Regards

Peter