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slide 1010
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( i% ?- ?1 }1 D* c) d0 ~) uFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
) }- @+ |7 Q4 w. X& w+ B" fThe signal bandwidth is determined by RF and not by the circuit gain.$ n9 }2 q$ m; g+ V- e7 A; F
The circuit gain is independently set with RS.+ b- H' l* t+ Q+ |
The signal bandwidth remains stable for all gain settings .
, Q, Q3 l/ U+ c# V9 [. G5 u& YEven for unity-gain operation, an RF resistor is required.
' s1 Z8 ^1 v( I8 ~% j& yThe 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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