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slide 10102 S3 i: n, e* {5 Q
- W! b- H6 ]. D2 p$ e' q8 UFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
, [ ], j$ }2 |The signal bandwidth is determined by RF and not by the circuit gain.8 V& U+ Y' z5 g4 D% l0 S' X
The circuit gain is independently set with RS.
7 l# u Y* v1 o& I2 sThe signal bandwidth remains stable for all gain settings .
. s+ k" J, R) E; Z4 @) ~3 xEven for unity-gain operation, an RF resistor is required.
2 g5 ?4 M. f4 a) q# ^/ y5 H. 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. j# |( {) I9 O4 v; T
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