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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. 8 _" b1 z0 {' ?' ?
The signal bandwidth is determined by RF and not by the circuit gain.1 H, D6 W r( W7 V$ s
The circuit gain is independently set with RS./ e; [9 b2 b0 ]( J
The signal bandwidth remains stable for all gain settings .
5 C' l @0 X# \3 Y. K9 W! XEven for unity-gain operation, an RF resistor is required.
* ]" t4 P7 j# ^& g- t/ ]5 pThe 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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