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slide 1010: K- {- {: [: @0 D- t
' U- L8 e E( c3 Y2 L# g$ MFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
% p# z/ c4 |- e. x; n7 mThe signal bandwidth is determined by RF and not by the circuit gain.$ V+ \+ k" ~2 t. O
The circuit gain is independently set with RS.
. k& T% @0 @7 _5 eThe signal bandwidth remains stable for all gain settings .
6 F3 T% C. B1 i9 ?( h* rEven for unity-gain operation, an RF resistor is required.5 t% T& i, T# C
The 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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