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slide 10106 L$ N# S: e* T, p! R
& } r; M q I8 J8 q: |) S* h iFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. ) b+ o4 m1 E/ r" I& d4 m
The signal bandwidth is determined by RF and not by the circuit gain.
" T* t0 k, N; sThe circuit gain is independently set with RS./ r! I. F, W5 @& l" A0 a3 d
The signal bandwidth remains stable for all gain settings .
+ P E0 q- `* I7 vEven for unity-gain operation, an RF resistor is required.
; I( Y0 a; g, @3 h) k, [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./ s# \- w4 W7 C% k) p
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