Help me with frequency gain unit for high speed (600MS/s) design

[wael_wael]

Hi everybody
i working with Pipeline ADC design, so i am looking to High spped (600MS/s), so i am i cam to design OP AMP, i started with frequency gain unit as folowing:

Wt=gm/CL
Fu=0.22(N+1).Fclck
N= number of bit
Fclck=600Mhz(same, ADC sample rate )
Fu=0.22(12+1) * Fclck
i f the current of Diffrential pair is 20uA, Cl=2pf then opamp need Fu=1.7160e+009
and W1=0.0251 meter(so crazy)
i want ask 2 question
1. how much widest w in Tsmc 0.18 process
2.can some one suggest some thing
regds

 

[eezou]

frequency gain unit

Can you explain Fu=0.22(N+1).Fclck ?