Abstract
This chapter discusses the current feedback amplifiers (CFA), which do not have the traditional differential amplifier input structure; therefore they sacrifice the parameter matching inherent to that structure. The CFA circuit configuration prevents them from obtaining the precision of voltage feedback amplifiers (VFA), but the circuit configuration that sacrifices precision results in increased bandwidth and slew rate. Constant gain/bandwidth is not a limiting criterion for the CFA, so the feedback resistor is adjusted for maximum performance. Stability depends on the feedback resistor: As RF is decreased, stability is decreased; and when RF goes to zero, the circuit becomes unstable. As RF is increased stability increases, but the bandwidth decreases. The inverting input impedance is very high, but the noninverting input impedance is very low. This situation precludes CFAs from operation in the differential amplifier configuration. Stray capacitance on the inverting input node or across the feedback resistor always leads to peaking, usually to ringing, and sometimes to oscillations. A prudent circuit designer scans the PC board layout for stray capacitances and eliminates them. Breadboarding and lab testing are a must with CFAs. The CFA performance can be improved immeasurably with a good layout, good decoupling capacitors, and low inductance components.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
