frequency formula of Ring Oscillator

[freewing]

Does anybody know the formula of the oscilation frequency in ring oscillator?

 

[odyseus]

have a look ay my tutorial at:

h**p://www.rfic.co.uk/RFIC_Circuits_Files/Ring_Oscillator.pdf

Ody

 

[kienhuy]

The period of the ring oscillator is twice the propagation time through the chain.

 

[freewing]

Thanks. But I'm talking about ring oscillator formed by differential amp stages. This ring oscillator has a higher oscillation frequency. It's not full-swing oscillator, which is the case in inverter chain oscillator.

 

[sadegh.raisi63]

Please Read this paper form IEEE trans "Closed-Form Analytical Equations for Amplitude and Frequency of High-Frequency CMOS Ring Oscillators", Payam M. Farahabadi, Hossein Miar-Naimi..
this is a good equation and has well analysis.