• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 510 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PCM2707C: Signal flow of I2S Interface

Haeseong Jo
Prodigy 180 points

Part Number: PCM2707C

Hello,

I'm going to use PCM2707C as a stand-alone DAC, or USB-attached when USB cabled connected.

I'm just wondering whether the below signal flow can be possible :

[ USB Audio from PC ]

=> (USB in PCM2707C) => (I2S OUT)

=> [ External I2S Device ]

=> (I2S IN) => (DAC)

Yes, an external I2S device is inserted serially in the signal flow.

On the block diagram in datasheet, there's no connection from I2S interface to DAC,

but It should work as the above, so I just want to make it sure.

And, one more thing : May I use PCM2707C bus-powered but detached from USB?

I want to use USB power adapter (such as smart-phone chargers) as power source,

and sometimes connected to PC as USB device, switchable automatically.

Is it possible? PSEL=1, HOST=1, but just power only, not as USB device.

  • 0
    TI__Guru 57800 points

    Hi, Haeseong,

    This device is meant to be used with USB connection at all the times, we cannot guarantee the correct performance of the part if used as a standalone DAC.  

    When the USB connection is present, the PCM2707C has only one output from the USB-audio device perspective. When pin 9 (FSEL) of the PCM2707C is set as '0', the DOUT signal from I²S interface will be used as the USB audio output. The input of the I²S interface (DIN, pin 4) will serve as the DAC input, the source for the analog output. So the signal flow you are trying to accomplish should work when USB is present.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer