I'm looking for a simple solution to convert microphone audio to S/PDIF stream.
Does Analog Device have products in its portfolio to achieve this functionality?
The ADAU1452 / ADAU1451 / ADAU1450 are automotive qualified audio processors that far exceed the digital signal processing capabilities of earlier SigmaDSP...
ADAU1452 on Analog.com
Yes, a couple of products.
The ADAU1452 has an SPDIF input and output. The microphone can directly interface with the DSP if it is a digital mic. If it is an analog mic then you will need some sort of codec to be a mic preamp and ADC.
The older ADAU1442 also has an SPDIF interface but it is an older part so I would not use it if possible.
Sample rate will be important. The ADAU1452 can go up to 96kHz fs and if you need to go up to 192kHz fs then you will need to use the ADAU1467/66/63/62 family.