We have a document "Wiced smart hardware interfaces" in the "Doc" folder within the IDE. Did you have a chance to review it?
I had read that and the datasheet for both the BCM20737 and BCM20737S. They state that the ADC conversion time is 10uS, however I have not been able to find any information on the tracking time. If the information is not available at this time I will attempt to measure it and post my results here.
Per the technical reference doc, with the pin configured as an ADC input, it should have 500k impedance on it.
I'm unclear on what you mean by tracking time. Our sampling rate is configurable. 5-8-187khz. Our Channel switching rate is 133.33 Kch/s.