Suggest me the architecture of difference Ring VCO!

[flyinspace]

Hello, everyone
I am designing a difference Ring VCO in CMOS 0.35um process. It's main specs are below:
Tuning range:10M-150M with wide input control voltage, 5v power supply, lower phase noise(I am not sure about the exact value, it is better when lower), better power supply suppression, good substrate noise suppression, output is square wave with 50% duty cycle
My design attaches important to the lower phase noise & better power supply suppression. At the same time, I select the difference Ring VCO due to the low frequency application. Who can give me some hints about the detailed achitecture? To abtain the better performance, how many stages is appropriate(3 or 4 stages)?
If you present a suggestion, please post your reasons together.
Thanks in advance.

 

[goodboy_pl]

u have mentioned all specs but the operating frequencu!

for GHz range + low tuning range (in percent) the LC oscillators provide the lowest phase noise to power consumption ratio.

the ring oscillators provise very wide tuning range suitable for digital application offen due to higher phase noise to power consumption ratio.

for LC oscillators there is only 3 useful topologies but symetric one is better due to flicker noise reduction and 1/2 required power (current reusing).

ring oscillators are made differential and single ended, both of them are used in IC design but according to papers two coupled single ended ring oscillator have the lowest phase noise for a determined power level.

BEST!

 

[flyinspace]

Hello goodboy_pl,
I appreciate your help very much! I have presented the operating frequency range--Tuning range:10MHz-150MHz.
Beacause my VCO is for low frequency application(Clock generator in MCU), LC oscillator is not appropriate for me. Therefore, I select the defference Ring VCO to reduce the Phase Noise.
You have mentioned "two coupled single ended ring oscillator have the lowest phase noise ". Can you provide the relative paper or the link for me?
How about the architecture of cascode using for Ring VCO?

 

[lxb97409]

For vco design,you can buy the book"the design of low noise oscillator",or you can search in google,there are much paper on it published in IEEE.

lxb97409