# Calculate ring oscillator (5 stages NOT gate) frequency

#### Faiz Valensi

Joined Jun 16, 2014
7
How to calculate the oscillation frequency of the ring oscillator? The capacitor for each of the NOT gate is 9.3pF.

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#### WBahn

Joined Mar 31, 2012
26,398
Usually it's done via simulation. But to get a rough estimate you need to determine the channel resistance of your FETs (which is also generally done via simulation, but you can also use the equations governing the FET in saturation to estimate it).

#### Faiz Valensi

Joined Jun 16, 2014
7
Usually it's done via simulation. But to get a rough estimate you need to determine the channel resistance of your FETs (which is also generally done via simulation, but you can also use the equations governing the FET in saturation to estimate it).

Yeahh, the value of the oscillation frequency in simulation is 8.3MHz, and i just need to calculate to proove it :/

#### WBahn

Joined Mar 31, 2012
26,398
Well, what's the channel resistance of your FETs when in saturation?