Which parts do you use for low noise synthesizers?

Dear all,

I'm involved in a 12GHz (and 25 GHz) low-noise synthesizers. Critical is to get as low phase-noise as possible with low to moderate price components.

What I have now is ~-80dBc/Hz at 100Hz, <-100dBc/Hz at 1kHz and higher at 12 GHz output. I'm using Hittite's integer PLL.

Which part numbers are you using and what kind of performance do you get?

Thanks,
rfmw

In fact your question is a little bit open ended...
What is your Loop Bandwidth ? Because after the corner frequency of the Loop Filter, the Phase Noise contribution is added by VCO itself.
So in this case what is your VCO's Phase Noise caracteristic ?
I mean, In-Band and Out-of-Band Phase Noise components are different and that's why the other component's such as Reference Frequency PN, VCO's PN etc...
It's not very meaningful to ask this question standalone...

Indeed you are very right, I was refering to inband phase noise ;)

Thanks for bringing this up.

If you're looking for synthesizers, hittite are best-in-class as far as I know. But they are not cheap and their power consumption is pretty high.

Analog devices is trying to get back, contact them for their newest components.

If you want to make the phase noise even lower and frequency agility is less of an issue, consider designing a DRO with sampling loop to multiply on a harmonic of 100MHz for example. Or you can do this with a VCO and low-cost PLL which you deactivate after you have locked to the correct frequency to let the sampler take over the lock.