|
slide 1010
" c6 `5 i, C7 A& K
3 ]" r# Y& o- A7 m0 \8 b# n# uFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. 7 b2 E5 G; v- n0 x# m3 x9 z
The signal bandwidth is determined by RF and not by the circuit gain.
) q2 q4 _* ^. E4 f5 _1 ZThe circuit gain is independently set with RS., v: s8 `0 }$ s( X6 v( z
The signal bandwidth remains stable for all gain settings .
+ K* S g% [, F1 \% p) h( U, [% EEven for unity-gain operation, an RF resistor is required.# W; ^" P$ U6 b& F
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.; b9 ?' K3 f; i. ?; }) u8 F
|
|