Calculating the Bandwidth of Voltage Controlled Oscillator

[ronniebra]

I have a current starved oscillator and was wondering how I could calculate the bandwidth of it?


I'm using Cadence Virtuoso and ADEXL. I tried to run an AC analysis on a 100mv magnitude AC wave input and checking the output of the VCO , but it doesn't give me anything usable. I'd appreciate any sort of help

 

[BigBoss]

There is no such thing "Bandwidth of VCO"..
There are "Tuning Range" and "Tuning Sensitivity/VCO gain" specifications.
Tuning Range is max. and min. available VCO Frequency.Tuning Sensitivity can be obtained by applying a DC voltage to Vtune and changing this voltage between min. and max. permissible limits.
It provides a Freq_VCO vs. Vtune curve.You can now predict Tuning Sensitivity from this curve because Tuning Sensitivity is NOT constant and varies by Vtune.

 

[ronniebra]

Thank you BigBoss, that's what I thought. We're using this VCO block with frequency to digital blocks in order to design an ADC. One of the given equations for ENOB and SNQR requires the bandwidth and we're just not sure how to find it.

 

[frankrose]

ENOB requires the bandwidth of ADC's input signal, not the clock frequency.