Other Parts Discussed in Thread: SN74LV4046A
I obsered excessive jitter at VCO_out, even if loop broken (at constant VCO control)
Jitter is ca 20 Deg peak-to peak.
f0=5MHz, Ct=220pF, R2 is ca 5K (using a trimmer), temporary no R1, VCO_In connectod to R2 pin.
VDD bypassed by 10uF Ta, 100nF X5R.
In my design tuning current "injected" to R1 pin (sink current source). I also experience the same jitter when no this I1 current (loop broken - of course in this case f0 somewheat lower since total internal current for Ct is the sum of (amplifeied - x6) I1 and I2).
If I use much larger Ct say 10nF, the jitter cannot be observed. I need jitter free VCO signal in case of low Cts.