|
slide 1010' g# P. @0 r2 S/ Y1 q
4 g! i6 r5 H0 B
For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. ) l9 R, `- {0 K% R* x
The signal bandwidth is determined by RF and not by the circuit gain.
& |* v/ `/ B" q9 uThe circuit gain is independently set with RS. ]1 \8 Z2 k! n5 D Q
The signal bandwidth remains stable for all gain settings . D" q1 E- ~9 l
Even for unity-gain operation, an RF resistor is required.1 V8 |3 S+ |! |; O3 I9 f
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.
( E8 `! |; F6 Z7 a |
|