Sync divider or async divider?

[qslazio]

what's the advantage and disadvantage of them?
as far as I know:
the power consumption of sync one is larger than async one.

So what's the other reasons why we should choose sync one while sometimes we prefer async one?
Please share your knowledge.
Thanks

 

[hanm]

The syn one has a better phase noise,while the asyn one consums little current.

hanm

 

[qslazio]

The syn one has a better phase noise,while the asyn one consums little current.

hanm

Dear hanm,
can you please tell me why sync divider has a better phase noise performance than async divider?

Thanks.

 

[sunking]

the speed. async is higher