in my opinion, the buffer in the first circuit is actually a source follower, it is indeed a buffer stage. input impedance is very large and the output is small.
the second one is an inverter. it is a buffer stage anyway.
回复 3#nicro
i do not know whether these papers are useful to you. i just download them from the IEEE. however, i do not know too much about buffer design, sorry. good luck
by the way, my computer has no the chinese input, sorry again.