1) Confirm RTC Minimum Voltage Specification
The datasheet for the SC589 that shows a minimum RTC voltage of 3.13 V for VDD_RTC on page 80. We are hoping to drive the RTC with a supercapacitor.
Most other devices have a minimum operating voltage in the neighborhood of 0.9-1.5 V from what I have seen and based on my brief bout of testing the RTC on the SC589 will operate at 2.25 at least.
The question is, will ADI be providing an actual functional operating range (guaranteed) other than what is outlined in the datasheet considering our intended use for the RTC? This drives our decision to use external RTC devices. Ideally we would want to stick with the ADI reference design.
2) Confirm S/PDIF Maximum Receive Sample Rate of 192 kHz
We require an input sampling rate of 192 kHz for our AES inputs (we plan to convert to S/PDIF and use the built-in transceivers), but ADI documentation is inconsistent as shown below. There is no spec in the datasheet, but the hardware reference manual makes reference to it. We have tested the S/PDIF interface and it happily accepts 192 kHz input. Our concern is that if it is not spec’ed at 192 kHz will it be supported in the future? Could we get some guidance from ADI on that issue?
“The S/PDIF receiver receives any S/PDIF stream with a sampling frequency range of 24 kHz to 96 kHz” SC58x-2158x-hrm.pdf 32-8
“The input to the S/PDIF receiver is typically 44.1 kHz if supplied by a CD player, but can also be from other source at any nominal sample rate from about 22 kHz to 192 kHz.” SC58x-2158x-hrm.pdf 30-8