Design a Sallen-Key lowpass filter

Thread Starter

kentman234

Joined Dec 7, 2018
3
Hello,

I have this task:

Design a Sallen-Key lowpass Butterworth filter with a 3 dB bandwidth of 8 kHz and 20 dB attentuation at 24 kHz.

Can you give me some hints?

Thank you.
 

Thread Starter

kentman234

Joined Dec 7, 2018
3
Hi,

yes. I think the normalized frequency for 20 dB is 24/8=3 Hz is that right?

So the 2nd order is enough. And what about calculating the elements?

I have the solution here. It says R=28.13 kohm, C1=1nF, C2=500pF.
 

bertus

Joined Apr 5, 2008
20,230
Hello,

Without a schematic I can not tell you if the values are correct.
Have a look at chapter : 16.3.2.1 Sallen-Key Topology of the given PDF.

Bertus
 
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