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slide 1010
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For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
/ h9 B+ V8 A( \ CThe signal bandwidth is determined by RF and not by the circuit gain.2 }1 ^2 R' [/ n
The circuit gain is independently set with RS.& F$ H0 Y' A2 s
The signal bandwidth remains stable for all gain settings .0 L# a% J( h/ G# U: r7 b3 j6 r
Even for unity-gain operation, an RF resistor is required.' G& n5 d) Y+ N. g( I8 b$ Q/ M7 G% J
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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