Other Parts Discussed in Thread: PCM1822
Tool/software:
Hi, I am currently developing an audio frontend for a portable synth application, and I had a couple of questions regarding the input impedance of the PCM1822 and its relation to its charge capacitor and line inputs.
I have heard it is generally recommended to have an input impedance greater than 10k ohms as to not load the line source too much. Considering the PCM1822 has an input impedance of 2.5k, I was wondering if this would result in distortion. I looked at the EVM schematic and there was no special input buffering to mitigate this. I get that the EVM is for testing, but are end users supposed to add some extra hardware at the line inputs or is that unnecessary? Additionally, if an op amp buffer before the ADC on line inputs is recommended, are there specific op amps I need to keep in mind? I have seen that with certain op amps; they are not fast enough to charge the sampling capacitor. Thank you.
