How can I tap off an I2S and get a line out signal?

I have a circuit that feeds a I2S bus into a PCM5101A chip, which outputs a analog signal that is used by the circuit. I have tried tapping into the analog signal coming out from the PCM5101A chip, but the sound gets distorted when there is a lot of lower frequencies in the music that is being played. My guess is that the rest of the circuit is interfering with the signal somehow making it distorted. I would like to get a clear sound signal and are therefore interested in tapping off the digital bus before it is converted to analog by the PCM5101A.

I have understood from previous answers here that tapping off the I2S bus is doable.

Would a device like this one do the trick? https://www.aliexpress.com/i/32807703240.html

If so, how should I draw the wiring in order to not mess upp the I2S bus signal?

Also if anyone could help me with which pins connect to where from the PCM5101A chip to the digital to analog converter device, it would be very appreciated. I could probably guess which one goes where, but since the connectors aren't named exactly the same it would feel better to get some help.

  • 0
    •  Analog Employees 
    on Feb 14, 2020 2:43 PM

    Hello sunkan,

    An I2S bus is simply a digital data transmission bus so as such you have to look at it as a transmission line. Any splits or sharp turns are impedance discontinuities and will create reflections. Those have to be damped. This gets a little complicated because there are a lot of factors. The drive strength of the circuit driving the bus, the length of the bus, the stray capacitance of the PCB and the devices connected to the bus, the impedance of the PCB traces. So it gets a little tricky. Regarding pinout, I suggest you contact TI for assistance with their part or the company that sells the Arduino products. There is nothing here that is an ADI part so I have limited info. 

    Dave T