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slide 1010- G& s: C8 P$ e. A9 J& g
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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.
; Y6 y3 Y% |. q: L X9 K0 P. VThe signal bandwidth is determined by RF and not by the circuit gain.
# _! R8 R- l7 D, a1 H7 IThe circuit gain is independently set with RS.
( j# B7 w8 X7 x: JThe signal bandwidth remains stable for all gain settings .
3 L0 o0 U$ f7 m) l6 M0 uEven for unity-gain operation, an RF resistor is required., H2 ?$ G1 }& W5 z4 W6 M, E4 `
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. K; ~7 ^/ V9 B
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