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Abstract

Two closely related dominant-pole-compensated feedback amplifier configurations have recently been developed specifically to exploit gain-bandwidth independence and offer constant-bandwidth operation throughout the full gain range. Do these two new amplifier types — the current-feedback amplifier (CFA) and the transconductance-feedback amplifier (TFA) — actually operate in a fundamentally different way to previous feedback amplifiers? Or are they able to avoid the restriction of a constant gain-bandwidth-product simply as a consequence of specific and non-optimum choice of feedback resistor values, with an inevitable cost in precision, sensitivity and bandwidth in comparison to their constant gain-bandwidth-product counterparts?

Keywords

amplifier design gain-bandwidth independence

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Generalised Analysis of Gain-Bandwidth Independence in Feedback Amplifiers

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References