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slide 1010
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For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
1 a' R- [6 l/ l: j# {8 U- CThe signal bandwidth is determined by RF and not by the circuit gain.
- X4 z! {' w9 y" gThe circuit gain is independently set with RS.
% R0 A% z+ m$ d5 T6 aThe signal bandwidth remains stable for all gain settings .6 ]) X7 F' j' s7 R5 _
Even for unity-gain operation, an RF resistor is required.
# U( n; N$ E2 EThe 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.5 `8 J4 C# |8 j4 u: X, H6 b6 P
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