zczc999
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Hello,
I am new to PLL design. I have a question that which level of charge pump current is suitable for a pll.
I know the current should meet the requirement of bandwidth, damping, etc. But which order of magnitude is preferable, say 10uA, 20uA, 50uA, or 100uA, considering matching, noise. Now I am using a 15uA charge pump, I don't know if it is too small.
And the current has glitches at the edge of switching signals. The glitch is about 30uA. Will this has big affect on phase noise?
BTW, to eliminate the deadzone of PFD, a delay will insert at the reset path. Usually how much delay is added? I think the smaller the better, as long as the pulse can turn on/off the switches, so I am using about 200ps. Am I right?
Thanks
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