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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.
?: X. b7 L; _( `The signal bandwidth is determined by RF and not by the circuit gain.
' k- y$ r1 \" G7 [1 jThe circuit gain is independently set with RS.9 Z9 J5 H3 h I# M9 z
The signal bandwidth remains stable for all gain settings .% d5 U @! E$ ^$ h$ y
Even for unity-gain operation, an RF resistor is required.) a, k% ~* M$ l* z# u0 y% r
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.) [( ~; @0 Q- N" e
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