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slide 1010, a: W" J; q8 j) F" h1 j, [
! M* [0 c$ q+ Y% }4 JFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
4 c* _2 x6 d9 i6 J2 a& [The signal bandwidth is determined by RF and not by the circuit gain.
3 Y$ h' T7 X% E! ?0 w* P% fThe circuit gain is independently set with RS.- W' z7 I$ n; i5 b+ h
The signal bandwidth remains stable for all gain settings .
) `( O) q3 V: c" j6 {Even for unity-gain operation, an RF resistor is required.8 V+ i& ^- I- Z) e& u- g* \
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.' ]8 k# o! @% n4 A: o
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