Hi,
  when iam using this dynamic comparator with equal inputs  iam not getting metastability state for the given circuit for different values of (W/L) ,,,,but metastability occuring only when the enable frequency is higher i.e is in Ghz range.
   Why i didnt get the metastability problem for low frequencies
Can anybody suggest me the solution ?


Thanks in Advance
srinu

How are you simulating metastability?  
Are you just looking at gross failures?   Noise analysis?

First, you should understand for yourself what metastability is. I'd define it as an event when a comparator cannot resolve the input within particular amount of time .
Secondly, metastability is a probability-thing, i.e it occurs always! At high frequency, comparator has less time to resolve input and so you see a lot of metastable events. However, it is very difficult to see metastability issue at low frequency because probability is much-much lower.