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slide 1010( N3 s- @) U# i: t+ e, g
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For a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
0 ~1 N# k% p1 J8 jThe signal bandwidth is determined by RF and not by the circuit gain.
, x3 Y2 p) f& [! m% z2 z* AThe circuit gain is independently set with RS.
" O( _( v* ~& M4 z1 }7 KThe signal bandwidth remains stable for all gain settings .* ], j( I# `' i! ~. a
Even for unity-gain operation, an RF resistor is required.
6 t5 X+ T4 G j1 u; RThe 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 Z% \" b9 F X ` o% u5 n- |
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