VCO tuning range between 80-90%

[AdvaRes]

Hi members,

I noticed that always the VCO tuning range is between 40 and 80 % of the nominal voltage.
What about VCOs in which the Tuning range is between 80 % and 90 % ?

 

[khouly]

VCO tuning range

the tuning range of the VCO depends on the CV curve of the varactor , so to get high tuning range u need the vacattor to have wide tuning volateg

khouly

 

[icsoul]

Re: VCO tuning range

You could do this with the control voltage of VCO in the related range.

 

[jecyhale]

Re: VCO tuning range

Hi members,

I noticed that always the VCO tuning range is between 40 and 80 % of the nominal voltage.
What about VCOs in which the Tuning range is between 80 % and 90 % ?

It is up to the CP output voltage range.
When the Vtune larger than 80% or lower than 20%, CP will be mismatch.
But if you use ADPLL, there is no problem.

 

[rfsystem]

Re: VCO tuning range

If the VCO could use only 10% of the supply as voltage tuning range it will be more sensitive to noise and tolerances. Typical designs try to maximize the range ro 20-80% which could be covered by either a chargepump or an opamp in an active loop filter.

 

[n1cm0c]

Re: VCO tuning range

As mentioned, if VCO tuning range is covered by 10% of supply then Kvco is very high, making it very sensitive to noise in the tuning voltage.

One designs for a tuning voltage between 20% to 80% of supply rail because that's about the max useful output range of the CP.

This way one can lower the Kvco and reduce sensitivity to noise in the tuning control line.

 

[rosaeidi]

VCO tuning range

Hi

Tuning range is depended on varactor network. You can have a tuning range from 2% to 100%.