Hello everyone,
I'm using the CS4272 (Datasheet) to convert I2S data to analog audio signals. The only thing I need to do is designing the output stage. CS recommends an differential output filter on page 33 of the datasheet. However, I've had a hard time figuring out what the filter actually does. I recreated the given circuit to make component numbering easier (see attachment).
The input stage of the codec's output look like lowpass filters (R1&C3 and R3&C4). Their output in turn is fed to a differential amplifier stage (R2, R4, C1, C2), although the feedback and ground resistors are capacitors (some kind of integrators?). C6 is definitely an AC coupling capacitor. R7 and R8 seem to be attenuating resistors. I have no idea what R5, R6 and C5 do. R6 and C5 may probably contribute to the lowpass filter's performance.
I don't have a lot experience with more complex filter circuits yet.
Am I on the right track? And where do all these values come from?
Thanks in advance.
I'm using the CS4272 (Datasheet) to convert I2S data to analog audio signals. The only thing I need to do is designing the output stage. CS recommends an differential output filter on page 33 of the datasheet. However, I've had a hard time figuring out what the filter actually does. I recreated the given circuit to make component numbering easier (see attachment).
The input stage of the codec's output look like lowpass filters (R1&C3 and R3&C4). Their output in turn is fed to a differential amplifier stage (R2, R4, C1, C2), although the feedback and ground resistors are capacitors (some kind of integrators?). C6 is definitely an AC coupling capacitor. R7 and R8 seem to be attenuating resistors. I have no idea what R5, R6 and C5 do. R6 and C5 may probably contribute to the lowpass filter's performance.
I don't have a lot experience with more complex filter circuits yet.
Am I on the right track? And where do all these values come from?
Thanks in advance.