Electronic – Regarding slew rates, what would be the minimum for amplifying audio using an op-amp


Many, many choices. And this is just Microchip's offerings.

I'm going to be amplifying by a maximum of 5x using an op-amp. So I choose an op-amp with a GBWP of 50 kHz * 5 = 250 kHz. That still leaves many op-amps. What slew rate should I be looking for? (with low distortion on the output.) And are there any other parameters to look out for, like input noise and offset?

EDIT: It seems I need to clarify. I'm only looking for a single channel op-amp for amplifying a mono signal with reasonable levels of distortion. I'm not looking for high quality prosumer gear audio.

Best Answer

the slew rate needs to be \$\geq 2\pi f V_{\text{peak}}\$ to not impart distortion on a sinusoidal signal.

\$f\$ = frequency of the sinusoid and \$V_{\text{peak}}\$ = peak voltage.

So in your case you'd probably use 20kHz for the frequency and whatever your \$V_{\text{peak}}\$ is to find your minimum slew rate.