|
slide 10109 F) ]' u4 D4 h! M, J Z% R
8 n+ ]! \& c+ q. zFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
& B# l L+ Y8 C# P5 H- P- K) m" `The signal bandwidth is determined by RF and not by the circuit gain.
* K+ ?2 g# [4 h4 FThe circuit gain is independently set with RS.& p, v3 ^; ~& K T2 v# V
The signal bandwidth remains stable for all gain settings .( R9 U$ A9 y0 W8 S' z
Even for unity-gain operation, an RF resistor is required.
# C4 p3 w* U+ EThe 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.
4 P# T K" Q& F6 w/ C8 {7 j" H4 s |
|