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slide 1010
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$ Q. h4 v* c/ j, j/ B, Z+ O" @' PFor a CFB amplifier the open-loop gain is ZT and its feedback factor is 1/RF, making the loop-gain TCFB = ZT/RF. * w0 c, m/ ~. ^9 H( S
The signal bandwidth is determined by RF and not by the circuit gain.
: F+ i4 i- _6 f5 E' ]The circuit gain is independently set with RS.
~( [, l! a( a% k4 r7 Z JThe signal bandwidth remains stable for all gain settings .; C' ~* s/ S; W
Even for unity-gain operation, an RF resistor is required.2 }. T" \2 d- k4 e& `$ Z& \& ~
The 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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