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slide 10107 j1 B; ?! W8 ?8 D a3 O
6 i& Z1 [" N' g; P% @' }* wFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. 9 }! u. \0 c) ^4 `3 L
The signal bandwidth is determined by RF and not by the circuit gain.
# }- | u# [# hThe circuit gain is independently set with RS.0 L' P% r$ A* G4 N- l7 \
The signal bandwidth remains stable for all gain settings .
% q7 t7 Y+ e% q" P. S LEven for unity-gain operation, an RF resistor is required.
: e5 }; w/ q% D8 C, r$ L4 m1 WThe 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.2 f/ u0 }6 P, x U. Q' g; ~
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