|
slide 1010( f) s; }* ~4 ~! I( y( O
0 z/ F6 x4 B3 @! W" ?6 `, G# _
For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
3 s7 `5 ?5 a _) Z# j. W: BThe signal bandwidth is determined by RF and not by the circuit gain.7 C% E, y- x1 e% E! I5 R
The circuit gain is independently set with RS.% h- H& e# k0 Q1 g1 m) V
The signal bandwidth remains stable for all gain settings .! V6 }) W6 V7 u
Even for unity-gain operation, an RF resistor is required.
; J0 [0 Y/ g3 ^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.
9 V+ C4 a6 p% Y4 P1 m+ k |
|