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slide 1010- M3 ~7 U$ R+ {8 T! P/ m
6 A" r3 z1 l) r$ Q$ M1 R7 ~# W1 M
For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. : g- \8 W- { g' a$ ^
The signal bandwidth is determined by RF and not by the circuit gain.
7 \5 W/ ?& {8 |! u1 PThe circuit gain is independently set with RS.
, _% V, a# Q( `; q0 K( aThe signal bandwidth remains stable for all gain settings .# L" H* q# R, k0 T, q0 C
Even for unity-gain operation, an RF resistor is required.
% M* N- Y, ~! bThe 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.! V# U3 t" b W
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