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slide 1010
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& i2 U8 @# v0 h7 p" X% b1 |# IFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. - y* ~3 I& R& L
The signal bandwidth is determined by RF and not by the circuit gain.
8 X, o5 G- c& W6 X9 k1 g t/ N9 aThe circuit gain is independently set with RS.$ ]" l) \) c( C1 S- {# e& S
The signal bandwidth remains stable for all gain settings .
) {1 Z5 ]- ?! ~% w4 N- f0 sEven for unity-gain operation, an RF resistor is required.
5 A- U6 |& I3 q! \) Q ?, z5 VThe best practice when designing with CFB op-amps is to use the RF values given in the datasheet and to adjust the desired gain level through RS.
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