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slide 10104 x3 ^5 b/ o0 B/ ^
+ }- j! C& ~( E7 h" L5 m5 yFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
0 f+ {6 f* n) U1 R+ D/ cThe signal bandwidth is determined by RF and not by the circuit gain.
3 K( }2 w1 T9 y: a6 ^The circuit gain is independently set with RS.
4 k! w4 h# k, }8 x2 J. T: J, i& VThe signal bandwidth remains stable for all gain settings .
& m$ l8 u2 e7 u" }8 d0 @! [Even for unity-gain operation, an RF resistor is required.
% y4 B% t/ T& e E& 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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