Texas Instruments PCM2902 SPDIF out

[Ishmael]

Dear all,

I've been browsing through the DIYAudio forum for ages.


A question.


How difficult is it to get SPDIF out from the Texas Instruments PCM2902.


Thank you very much in advance.

 

[Mark Tillotson]

It looks like you just have to pipe it through a 75ohm driver at the correct S/PDIF level, its a low current 3V logic signal from the chip pin. The datasheet is a bit sparse on the subject.


Note the PCM2900/2902 are not recommended for new designs.

 

[Ishmael]

Thank you for your reply.

Forgive my lack of knowledge here.


Does that mean that all I need is to solder a +/- cable to the pin outs of the
chip and connect to standard RCA and use a 75ohm cable to get the signal out
to my DAC?


How do I get the SPDIF signal to the correct level?as I'm trying
to retro fit SPDIF to a mixer that has the PCM2902 inside and digital out except for the DAC that is being used as a usb interface.

 

[Markw4]

Looks like the SPDIF out is LVCMOS (DOUT on pin 25). If you need to drive a 75-ohm SPDIF cable/terminator, you will need a buffer circuit.

One possible approach:
First convert LVCMOS to TTL, such as by using a level shifter part such as the chip used on Sparkfun's board: BOB-11771 SparkFun Electronics | Development Boards, Kits, Programmers | DigiKey
Once you have TTL levels there are various ways to do it, one resource is at S/PDIF output - HwB

 

[Ishmael]

I have some learning to do.
Looks very promising though.


I'll most probably be asking some more questions.


Thank you very much.