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slide 1010
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" y, y; j U. F: h" G0 tFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. , X8 z/ i0 b) e& F$ ?: ~0 }. u: Z7 q
The signal bandwidth is determined by RF and not by the circuit gain.
) e- X( ^2 M6 R8 uThe circuit gain is independently set with RS.% Y9 c X/ I6 q. w& M
The signal bandwidth remains stable for all gain settings .
6 G; z+ B; M/ o+ v! V6 N+ A1 wEven for unity-gain operation, an RF resistor is required.. r8 q+ B! Z+ T2 U0 p( U
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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