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slide 1010
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3 K8 D# _9 b; D/ i/ lFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
/ Q" c. ^' ~1 {9 S2 V t9 Z0 J0 fThe signal bandwidth is determined by RF and not by the circuit gain.
9 ?& _/ I, w2 m- x+ }The circuit gain is independently set with RS.
c! X6 F; b* SThe signal bandwidth remains stable for all gain settings .7 U# ?1 r, T7 w" A: p( v2 V* @
Even for unity-gain operation, an RF resistor is required.
) `9 n3 p/ K l% T# \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.* M; K! \+ n8 S- c: c
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