VCO design question i.e., VCO frequency range

[coolstuff07]

Hello,

Iam designing Ring oscillator based PLL for range of 400MHz to 4GHz output. iam seeing good results but is it suggestable having such wide range because VCO gain will be very high or it is suggestable to have bands of frequency.

Bye.

 

[FvM]

Mainly depends on your performance specification. I wonder if the "good results" already consider unavoidable real-world effects, particularly jitter. The latter most likely suggest to restrict the frequency range to e.g. 1:2.

 

[coolstuff07]

Hello,

If VCO output frequency range from 500MHz to 4GHz single band what can be other problems.

Bye.

 

[dick_freebird]

The more range you have, the more you translate tuning
voltage / current noise into phase / frequency noise. So
in a communications system you want no more tuning range
than you need for your band of interest, and would prefer
most likely to switch narrowband sources than pull a wide
range VCO.

 

[coolstuff07]

Hi,

Iam designing it for Serdes.

Bye.

---------- Post added at 07:07 ---------- Previous post was at 07:06 ----------

Hi,

How to create bands.

Bye.