SpectreRF seems to have a problem with switching the units for your example (Amp instead of Volts).
The gui team is planning to fix it soon. If one in doubts, it is always helpful to look at results using
Result Browser tool or to go directly to the files in /psf directory and look it up.
As far as tdnoise results, one need to realise that it is a sampled noise measurement, not power vs. time index. There is
an aliasing effect due to the sampling, more information is available online and in the Switch Capacitor paper on this site(Analysis section).
To compare (which is only possible for a stationary white noise case), it is important to select the proper value for maxsidebands in
PNoise, and to integrate from 0+ to FreqPSS/2 only. The fact that you get such a high value for sampled noise PSD at 1MHz (40.4u)
tells me that you set maxsideband to something like "100". Due to sampling nature, it gives you 101X higher results for both PSD
and integrated total power. There might be a factor of two somewhere (like maxsideband is 50) but it is hard to say without exactly
reproducing what you are doing.
Again, tdnoise is sampled (or strobed) periodic noise analysis, not simply noise power vs. PSS phase. Please read the
document:
http://www.designers-guide.org/Analysis/sc-filters.pdfRegards,
SP.