1) What is the input impedance of the analog inputs? I need it for designing the microphone amplifiers.
Differential inputs with 10 kOhm each to GND.
2) Is there exact sampling of all 24 channels at the same sample time or have I to expect delays in between the channels?
All channels are exactly the same, except CH7/8, 15/16 and 23/24 which have a few samples more latency.
What about the time jitter of the sampling?
DCO-based clock recovery based on crystal oscillator –jitter is not zero but should definitely not be an issue.