Other Parts Discussed in Thread: BUF634
I Designed with this circuit by TI Filter design, with OPA 2890.
The 4.2 kHz filtering circuit ran as intended.
But when I only change the center frequency 4.2 to 5.5 kHz,
It has been confirmed that the Attenuation(Asb) ratio becomes 5:1 instead of the intended 40db (100:1)
I used OPA2890 Instead of BUF634.
I think the max Q value is so high for current circuit ,
So I changed the Passband Bandwidth(BWp) from 50 to 60hz. By so, Circuit adjusted the maxQ to less than 100 (87.23) and tried to proceed.
But I didn't get a good result at Asb.
Giving 5.5 khz to input : 150mV . Giving 5.2kHz to input : 30mV . Its attenuation is not 40dB.
What is the cause of the problem and what should I do to get the desired attenuation ?
