Both filter ICs are not really needed.
I remember the hype when they came out, but there were not many applications, certainly not in the audio world, in fact never saw them used anywhere.
Oversampling, delta-sigma and filtering on the digital side do not require 10th order analogue filters on the output.
Industrial applications needed higher frequencies soon, and there was the problem of 2nd sourcing.
A 2nd order filter LP/HP is done with 2Rs, 2Cs and an opamp, no need for clock circuits interfering with digital converters in the signal chain, a dual pot makes them adjustable in case.
I remember the hype when they came out, but there were not many applications, certainly not in the audio world, in fact never saw them used anywhere.
Oversampling, delta-sigma and filtering on the digital side do not require 10th order analogue filters on the output.
Industrial applications needed higher frequencies soon, and there was the problem of 2nd sourcing.
A 2nd order filter LP/HP is done with 2Rs, 2Cs and an opamp, no need for clock circuits interfering with digital converters in the signal chain, a dual pot makes them adjustable in case.
A while back I saw a state variable filter chip made for audio use. It did not have onboard caps like this one, but it did have precision matched resistors on chip.
It seems like a simpler solution for this application would be just fine.
It seems like a simpler solution for this application would be just fine.
I know this is old, but I want to use a lpf @1kHz with a commercial dac output to use as a signal for some testing in audio circuits. The .1% distortion in this setting shouldn’t matter should it?
Sorry if this is a stupid question.
I suppose the signal could have higher distortion after the filter than the bare dac signal.
Sorry if this is a stupid question.
I suppose the signal could have higher distortion after the filter than the bare dac signal.
1k series resistor and 0.15uFd cap to ground is about 1kHz first-order filter. Is that not enough?
The UAF42 vanished because it was just a few 19-cent opamps and resistors, which you could as well build yourself, even using the charts in the UAF42 sales-sheet.
The UAF42 vanished because it was just a few 19-cent opamps and resistors, which you could as well build yourself, even using the charts in the UAF42 sales-sheet.
I thought I might get away with less noise because I saw what must have been an outdated Burr Brown data sheet that said .004% thd+n. I looked at the later TI one and it says.1%. Waste of time as you suggest.
I need a low noise lpf to use with a good dac to generate a 1kHz signal to calibrate an adc.
I need a low noise lpf to use with a good dac to generate a 1kHz signal to calibrate an adc.