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.

Using PCM1681TPWPRQ1 and the TAS5514BTDKDRQ1 in an Automotive Design Application

Other Parts Discussed in Thread: PCM1681

I am working on a design which uses the following Texas Instrument parts: PCM1681TPWPRQ1 and  TAS5514BTDKDRQ1.

The PCM part is an Audio DAC which feeds 4 audio outputs to an external connector. The other 4 audio outputs are sent to the TAS5514B

Audio Amplifier.

I have includes a low pass filter at each of the 8 Audio DAC outputs. I have modeled the Low Pass Filter from information found on page 32 of the Audio DAC datasheet. I am using VCOM to provide a bias voltage for the for all 8 Low Pass Filters. 

I will upload the schematic pages of interest. Can I get a review of these schematic pages. 

I am particularly interested in the audio connections between the AUDIO DAC and AUDIO AMPLIFIER, Since I have a low pass filter at the DAC

what filtering do I need at the Audio Amplifier? Just the DC Blocking cap? As far as the 4 Audio DAC outputs getting sent to an external connector. I am sending VCOM to this connector as well.

5150 SCH pages 19, 20, 21 and 25.pdf

  • Hi Tom,

    Typically you will want an RC filter to act as a low pass filter to reduce or eliminate the out of band noise generated by the DAC noise shaping. You will also want the DC blocking cap after the RC filter. I will take a look at this in the nest day or so and get back to you when I have looked over the schematic.

    Justin
  • FYI
     
     
      
     
       Tom Roberts • Sr. Electrical Engineer
        
     
       
     
    Important Notice:  This e-mail and any attachments are confidential, may contain trade secrets and may well also     be legally privileged or otherwise protected from disclosure. If you have received it in error, you are on notice of its status. Please notify us immediately by return e-mail and then delete this e-mail and any attachment from your system. If you are not the intended recipient, please understand that you must not copy this e-mail or any attachments or disclose the contents to any other person. Thank you.
     
  • Hi Tom,

    Sorry for the delay. Looking at the schematic it seems you have redundant caps, you have an electrolytic DC blocking cap on the end of the active filter for the PCM1681, and then you have a ceramic DC blocking cap on the amplifier side input circuit. I don't think both are necessary.

    As for the PCM1681, everything else looks good.

    Justin
  • Hi, Tom,

    I think my colleague, Gregg Scott already provided you feedback on the TAS5514 section. If not, let me know, and I'll look it over for you.

    -d2