Unlike VFB op amps, the inverting input impedance of a CFB op amp is very low. This is advantageous when using the op amp in the inverting mode as an I/V converter, because there is less sensitivity to inverting input capacitance than with VFB.
A CFB op amp, on the other hand, presents a low impedance (RO) to fast switching currents even before the feedback loop is closed, thereby limiting the voltage excursion without the requirement of the external diodes. This greatly improves the settling time of the I/V converter.
