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slide 1010
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& {/ ?4 q6 K( w# I. ?% j' dFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF.
) R0 C: K, E7 _ _9 C( K' BThe signal bandwidth is determined by RF and not by the circuit gain.9 C) l4 O8 d7 D/ C; j+ z
The circuit gain is independently set with RS.
" G2 l( @9 ~; s. D6 lThe signal bandwidth remains stable for all gain settings ./ Z% F4 e. l( N
Even for unity-gain operation, an RF resistor is required.
1 ~ L L$ Z( k7 J! 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.
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