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DIX9211: Using DIX9211 in standalone DIT mode, possible to wire output directly to an RCA connector for coax S/PDIF out, or external amplification necessary?

Isaac Terrell
Prodigy 10 points
Part Number: DIX9211

Tool/software:

Using a DIX9211 for S/PDIF stereo out, from I2S input from a microcontroller. (This seems possible to achieve in "standalone DIT" mode.) Is the S/PDIF output that is obtained at MPO0 / MPO1 able to be wired directly to an RCA connector for final output, or will some kind of external amplification or buffer be necessary in the circuit? Intended rx device is consumer audio, for instance an integrated amplifier or an outboard audio DAC.

Also, when running standalone DIT, am I correct to assume that it is NOT necessary to connect VCC / AGND and the required functionality will operate from DVDD / DGND only? The datasheet helpfully says that VDDRX / GNDRX can be no-connect if the coax input amplifier is not used, but I did not see any remarks about whether the same thing is true for VCC / AGND if the DIR itself is not used.

Best, Isaac

  • 0
    TI__Mastermind 26761 points

    Hi Issac, 

    S/PDIF is a digital signal . For the S/PDIF coaxial interface you need to use a 75 Ohm coaxial cable and RCA phono connectors to connect it to your  device for processing.

    I don't have access to the actual schematics to confirm , but since VDD and AGND  are for PLL block, I also tend to think it is not needed for DIT.

    Regards,

    Arash

  • 0
    Prodigy 10 points

    For the reference of anyone coming across this thread in the future, the answer to my question was "No." Consumer coax SPDIF inputs are expecting a logic level of maximally 0.6 Vpeak whereas the DIX9211's DIT outputs are CMOS level 3.3 Vpeak. Finding a logic level shift IC that can achieve shifting to this low level is difficult. It appears to be the case that the DIX9211 DIT may only be suitable for driving Toslink outputs.