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slide 1010; m9 A- y. L6 m
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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. - H1 \2 x2 }9 z# x0 Y! `4 h9 E
The signal bandwidth is determined by RF and not by the circuit gain.0 ?+ U$ K/ }/ w1 p8 _, {5 G
The circuit gain is independently set with RS.# j$ o( j: R, W5 }
The signal bandwidth remains stable for all gain settings .
7 X. U+ F. o4 B- f0 ]4 U) `Even for unity-gain operation, an RF resistor is required., G9 m$ T/ J0 o: P. J0 p2 V
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. z* \) b( ~/ s' x3 W
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