|
slide 1010
; f) s! @5 V$ Z8 L2 {! _% w! @$ Z# Y, g9 P6 y0 O' p
For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. ; V1 B' w9 ~& Q
The signal bandwidth is determined by RF and not by the circuit gain.. _7 V' B9 |* d
The circuit gain is independently set with RS.
7 s; A, I' f xThe signal bandwidth remains stable for all gain settings .$ z- O# W7 Y4 J, F5 F* s! s2 L+ `. E
Even for unity-gain operation, an RF resistor is required.
9 X, _/ l, ]3 _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 H, q0 n# u* K4 z3 r+ N |
|