ic_engr
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Hello All,
I ran pss and tdnoise in spectreRF to estimate jitter for my oscillator. My ring oscillator is a differential relaxation oscillator with frequency of 4MHz. The last stage has differential to single ended converter.
I have following clairifications to be done:
1) Should I perform noise simulation on one of the differential output of the inner-stages of the ring oscillator or should I use the output of the differential to single ended converter output ?.
to get jitter I am integarting noise from 22KHz to 4MHz in tdnosie form. I get 390mV which I divide by Slew Rate of 330MV/s I get a jitter of 1.02nsec. This is in agreement to what I got on silicon in a 30us Time interval Error a measured jitter of 1.4nsec.
If I integrate from 25KHz to 4MHz, I get the noise as 53.6uV which then divided by Slew Rate gives a jitter of only 0.13psec. This is much smaller.
On what basis do I chose the BW for integrationin tdnoise form. ?
Why is the noise so different between the two BWs, 2khz-4Mhz or 25KHZ to 4MHz. ?
The jitter estimated in the BW is what, periodic jtter, longterm jitter or what ?
Any feedback will be greatly appreciated.
ic_engr
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