aaron_do
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Hi,
an ideal op-amp based filter only has a feedback path. However, a real filter will have a feedforward and a feedback path. The UGB of the loop gain will determine up the what frequency the BP filter will behave ideally. Beyond the UGB of the loop gain, the feedforward path will start to dominate, and the filter transfer function will no longer follow the ideal transfer function.
So the UGB requirement of the loop gain is determined also by your interferer profile and possibly noise requirements.
Also remember that even if the transfer function continues to roll-off after the UGB of the loop gain, the linearity will not be good at these frequencies.
cheers, Aaron
BTW as Raja mentioned, if you overdesign the opamp, you will pay for it with higher power consumption.
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