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slide 10101 |, X3 L* O3 E
! M) ]: {: x# s$ r* ^ ~: GFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
/ v3 x# G" i; C( P' [The signal bandwidth is determined by RF and not by the circuit gain.+ ^9 }8 o( x$ B
The circuit gain is independently set with RS.5 Q; p& C* v1 ~4 z" S' f
The signal bandwidth remains stable for all gain settings .
7 k' z( ^7 ]* l6 `8 S3 SEven for unity-gain operation, an RF resistor is required.& H" V$ u2 F6 o( C/ S
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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