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slide 1010; {$ a0 ~# W& d
i( \# p: Q" e0 J$ h0 WFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
$ }% A# e- ^, C) a2 CThe signal bandwidth is determined by RF and not by the circuit gain.
9 O( K) h3 y1 L3 p/ b4 yThe circuit gain is independently set with RS.5 J8 y3 X- c( p# ^1 C1 L- U
The signal bandwidth remains stable for all gain settings .
" v7 R5 T/ u5 ]3 w3 _8 o5 Z+ cEven for unity-gain operation, an RF resistor is required.
. d2 @/ a( a' a+ e! E$ [4 G% QThe 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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