PowerWise® Design University

Amplifiers 201 - Current Feedback Operational Amplifier

Referring to this graph, Frequency Response vs. RF, from the Feedback Resistor section, describe the gain behavior with an RF of 200 Ohms.


Over damping.
Under damping.
Peaking.
Oscillation.


What is the most popular filter topology for a current feedback op amp?
Sallen-key
Butterworth
Bessel
Multiple feedback topology

If you have oscillation, which of the following is a possible cause?
Capacitive loading.
Inadequate supply bypassing.
Feedback resistance too small.
All of the above.

Referring to the Spice Model from Optimizing the Isolation Resistor, how much peaking is there for 18 pF with RISO equals 3.9W?
55 dB
23 dB
100 dB
20 dB

What does the input stage of a current feedback op amp have that is different than that of a voltage feedback op amp?
A differential pair.
A Darlington pair.
An input buffer.
None of the above.

Referring to Isolation Resistance vs. Capacitive Load from Driving a Capacitive Load, if you have a 60 pF capacitive load what value RISO should be used?


90 Ohms
15 Ohms
30 kOhms
30 Ohms


What limitations should be considered when comparing a current feedback op amp to a voltage feedback op amp?
The buffer configuration needs a feedback resistor.
Vos is not systematically zero.
Both of the above.
None of the above.

How can you assure that a properly designed current feedback op amp will be stable at all gains?
Use the recommended RG value.
Use the recommended RF value.
Chose a small gain.
None of the above.