"splitting" I2S signal to 2 different DACs

[Sandm0n]

Hello,

I have a DAC with 3 digital inputs (coaxial,Toslink,USB) with WM8805 receiver, I would like to know please if I can split the output of the WM8805 I2S with another DAC so the 2 DACs will receive the same I2S signal at the same time?
Can I just connect the I2S output from the WM8805 to the 2nd DAC or do I need something more complicated than simple connection?

Thanks

 

[weissi]

It will work with a simple parallel connection of the two DACs.

 

[Sandm0n]

Thanks

 

[Ken Newton]

Also, make sure to program both DAC chips to accept an I2S formated input. There are other 3-wire digital audio formats which most DAC chips can accept besides I2S.

 

[weissi]

It is also good practice to have some series resistors in the I2S lines. Something like 47Ohm will be a good start.

 

[Sandm0n]

It is also good practice to have some series resistors in the I2S lines. Something like 47Ohm will be a good start.

What is the purpose of the 47ohm resistors?
Is it a "must to do"?

 

[Mark Tillotson]

Preventing/reducing signal reflections for high speed signals, and controlling rise/fall times and damping ringing. They usually go just before the chip inputs. No its not a must, as I2S is quite slow by logic standards - except MCLK if present. At 100MHz+ its highly important to have carefully controlled impedances on the logic traces which act as transmission lines at these speeds. At those speeds LVDS is commonly used too.

 

[Sandm0n]

Thank you for the detailed explanation.