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VCO deisgn without passive element

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khorlipmin

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What is the best topology for a non-passive element VCO using just CMOS transistors? Can anyone suggest some layout styles of the ring oscillator? Cheers!
 

cmos_dude

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A differential delay cell topology is a better alternative to using an inverter chain for the ring VCO.
The differential delay cell is less susceptible to noise and provides better control of o/p freq wrt to the i/p voltage.
 

khorlipmin

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Thanks Ahmad for the lecture notes, I can use some of them. :)

thanks cmos_dude for your advice,
My work need me to compare different topologies, and implement the best to provide 1GHz VCO with low power and low jitter.

I am looking at 3 topologies:

a) transmission gates + inverter VCO
b) current starved VCO
c) source coupled VCO

so when you said differential pair VCO, do you mean (c) source coupled VCO?
And can anyone with any information on these topologies please give me a shout? Cheers!
 

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