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TPA6133A2: Single supply, ground referenced output

Tom Allyn
Prodigy 30 points
Part Number: TPA6133A2
Other Parts Discussed in Thread: PCM2912A

I would like confirmation that this part will work with a 5v single-rail supply and a 150-5150 ohm, ground referenced, mono headset. I am using a PCM2912A headphone output as the TPA6133A2 input.

Should I float the HGND from the PCM2912A and consider it a differential input to TPA6133A2?

Do I still need the DC blocking caps on the input?

What is the best way to terminate the unused channel?

I will not be using the shutdown mode, but is it advisable to put a cap on the ~SD input to give the power time to stabilize and reduce start-up pop?

Thanks.

  • 0
    TI__Guru* 84915 points

    Hi, Tom,

    Welcome to E2E and thank you for your interest in our products!

    - Yes, the TPA6133A2 support a 5V single rail supply. The minimum load resistance that it supports is 12.8ohms. So, the resistance range that you mentioned is supported.

    - All xGND pins of the PCM2912A must be always tied to GND. Otherwise, there could be a device misfunction.

    - Yes, DC blocking caps are always required in a codec-amp connection. I actually also recommend to add an out-of-band filter between the codec and the amp. Usually the audio codecs work with a high-frequency modulator for oversampling. This high-frequency could be added at the amplifier stage and there could be risk of additional noise on the analog portion. Please take a look at this document for details about the out-of-band noise ( https://www.ti.com/lit/an/slaa313a/slaa313a.pdf ).

    - The analog inputs of the unused channel must be always AC-coupled to ground. A 0.1uF capacitor is recommended. For the analog outputs, they can be left floated.

    - I think the SD capacitor is not required since the SD pin depends of a digital logic level to change from high to low state. In case you have a signal with ripple noise at the SD pin, probably a small capacitor (~10nF) could help, but since the logic level threshold is relatively wide, I think there's no need to add the capacitor.

    Please let me know if you have additional questions or comments.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 30 points

    Hi Luis,

    Thank you for the assistance. I just received the EVMs for the two parts today, so I will do some testing and let you know how your recommendation worked.

  • 0 in reply to Tom Allyn
    TI__Guru* 84915 points

    Hi, Tom,

    Thank you for your response. I will be waiting for your feedback.

    Have a good day!

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 30 points

    Hi Luis,

    The system works great and there is very little noise with the EVMs. Thank you again for the help.