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slide 1010
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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. 6 u6 b6 Y4 W0 E9 X2 y+ f6 k
The signal bandwidth is determined by RF and not by the circuit gain.7 v, G& `' o8 ^$ J! t) ~
The circuit gain is independently set with RS.. K) D7 D# l+ B" F! i
The signal bandwidth remains stable for all gain settings .( x, B6 { @+ ^5 P- d! t+ T) i
Even for unity-gain operation, an RF resistor is required.
" \# z8 _" }+ M/ j; IThe 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.
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