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slide 1010
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- f+ y: K `4 V* H8 m4 t* xFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
0 l1 Q% j& A) q, T4 j, JThe signal bandwidth is determined by RF and not by the circuit gain., N; j8 D {5 g- B$ U4 v, Y# t- C( D
The circuit gain is independently set with RS.
( Q: n. f, Z0 @: s: E4 x9 H8 aThe signal bandwidth remains stable for all gain settings .3 N* Z! k/ l5 \. V8 P. R/ f
Even for unity-gain operation, an RF resistor is required.( D+ g5 p/ j3 t8 V0 ~! u, J
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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