Faye wrote on Jun 17th, 2015, 8:28am:Hi Raj,
The reference frequency is 1GHz, Kvco is pretty high at about 1.6GHz*2pi/V since it is a ring oscillator. Icp is 50uA and R=1.5K, C1=20pF, C2=2pF. The bandwidth is about 25MHz based on the parameters.
Thanks,
Faye
Good grief.
First, look at your architecture.
Do you really want a DLL instead of a PLL?
If you *really* want a PLL with PD/CP/LF, then there are some well known ratios of Refclk to LF bandwidth, which I'm pretty sure are being violated here.
Last, think about your KVCO.
You didn't spec your supply, but say it's 1V. You don't want to operate near the rails. You didn't spec your pull range, but say it's +/- 100 MHz. So you'd want a little more than 200 MHz / V, about a factor of 5-10 less than you have now. Excess gain will pick up noises.
Wave