Why phase locked loop(PLL) are asynchronous circuits?

[rakesh02]

hi,
can any one explain why phased lock loop (PLL) are asynchronous circuits.....can any one explain with example..

 

[FvM]

Are they? Phase detectors may be asynchronous, but phase-frequency detectors are always synchronous, also frequency dividers involved with PLLs have to use synchronous logic.

Please explain your question...

 

[kenambo]

Hi,

We cant say like that .. according to my point of view they are Synchronus only.. Because they all depend on Reference clock input..

Thanks