Say  you have CML buffer with nmos current source.

How do you size this nmos current source.

Ideally you'd like large L (to improve gds) but do you care about capacitance on the common node (ie the node connection the current source to the diff pair)? As you increase L, this capacitance increases.

What is the effect of this current source impedence on the overall performance of the CML driver?


i am assuming the signal is very high frequency ~ 10G