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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. , I: s! r4 }5 B6 Q2 B9 Z
The signal bandwidth is determined by RF and not by the circuit gain.
6 l% x$ E- u9 F( s' }2 E; xThe circuit gain is independently set with RS.7 J9 j6 V# @) L. S$ b
The signal bandwidth remains stable for all gain settings .
2 I- K- b8 Q& |# K& Z! NEven for unity-gain operation, an RF resistor is required.' @, O) [' J: ~/ e. ]
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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