generate high freq. clock from a low freq. crystal

[wuliao]

Hi,

I need a circuit to generate 250MHz to 350MHz clock using a low freq. crystal (under 50MHz). The high freq. clock needs to have phase jitter < 10ps.
Are there good PLL or circuit for it?

 

[judean]

HI,
For the requirement of jitter <10ps, I think PLL should be the best option. What kind of VCO are you looking at?

 

[rjshmadala]

Hello,
PLL is good option.u r working with very small frequencies, so getting of less jitter is not a difficult task.

Regards
Raj

 

[tfwee]

Ring Oscillator VCO design should be sufficient for your application. Of course, a fully differential structure should improve the jitter performance.

 

[Teddy]

yes there are - look into ICSt.com into their PLL portfolio.
Issue is that cheap devices are running xtals upto 27MHz so they do not use the overtone.
But if you have 25MHz xtal and multiply it by 10 you got what you need and 10ps should be feasible.
If you promise big volumes I will make one for you!