Part Number:OPA2890
Before I leave this newer (to me) BP filter topology, I stepped through a more demanding design targeting total 6dB gain with 1MHz center and only 50kHz BW forcing a 4th order solution in Filterpro. It does not support this topology, but using a MFB, it asks for > 1.5GHz GBP for the Q of 18 in each stage. That is too high a Q for MFB designs - and, while a mixture of computation and iterative R adjustments got the nominal design pretty close with the DABP approach, the response spreads are actually pretty high even using 1% C and 0.5% R. The implementaiton with a much slower (130MHz GBP) is pretty close nominally so it is possible to use a much slower device here than Filterpro suggests, but it would be interesting to test the shift to some GBP spread in the model - later.
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