Low Pass Filter for LM386

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isaac12345

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Hi, I'm using an lm386 to get a standard gain of 20. I'm using it in the config mentioned in the datasheet for a gain of 20. But I would like to alter its frequency response so that it cuts off frequencies higher than 20khz. Could someone please suggest where the low pass filter compenents will be place for this? I tried pin 5 but it gives me incorrect results.
 

Like many other audio amplifiers, LM386 has a minimum stable gain (of about 10, I think), so you must not apply any of those circuits, the place a capcitor between output and inverting input, e.g from the first link.

A simple and safe way would be a first order low-pass at the input. Also a second or third order positive SAB low pass, corrected for the gain of 20, should work.
 

Sorry about that, i didn't check the opamp specification,
I have just posted some tutorials on low pass filter design .

Alex
 

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