Current feedback op-amps

Re-visit the non inverting amplifier
V IN
Y G
+Y F
Z
V OUT
Y F
The CFOA is a transimpedance amplifier, i.e. equivalent to the block diagram
The response is, in terms of the transimpedance Z is the usual FB expression:
G
NINV
( + )
Z Y Y Y Z
= ⇒ lim GNINV
= 1+ = 1+
1+
ZY Z →∞ Y Z
G F G F
F F G
Notice that the loop gain is ZZ F
and that Z is typically second order beyond
the first pole, so that, for a parallel RC in the feedback path we get a second
order underdamped system.