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TAS5508: TAS5508

Tomasz Pisarek
Prodigy 10 points

Part Number: TAS5508

Tool/software:

Hi,

In the TAS5508 datasheet there is an example schematic showing the connection to 2 Channel Line Out (TLV272) using PWM_P and PWM_M lines.

Could I ask for a schematic of the 2 Channel Line Out (TLV272) module, please?

I have an audio amplifier with TAS5508 and I would like to add a line output to the center speaker via the TPA3116D2 amplifier.

And I am missing a schematic of this PWM to analog converter 2 Channel Line Out (TLV272).

Thank you very much for your help.

Tomasz.

  • 0
    TI__Guru**** 184576 points

    Hi,

      First of all, please be aware that this device is NRND. 

    Tomasz Pisarek said:

    In the TAS5508 datasheet there is an example schematic showing the connection to 2 Channel Line Out (TLV272) using PWM_P and PWM_M lines.

    Could I ask for a schematic of the 2 Channel Line Out (TLV272) module, please?

    I'm not clear with your question. TLV272 is a OpAmp. The datasheet and other documents can be found at https://www.ti.com/product/TLV272#tech-docs. The functional block diagram is shown in the datasheet. 

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Hi Charles,

    Thank you for your answer,

    I know that TAS5508 is old, but I have one installed in my amplifier and I want to use the unconnected center speaker channel (PWM_7)

    I also know that to convert PWM_P and PWM_M to analog signal I have to use OpAmp.

    but in the documentation there is an example of LPF, where only one signal is supplied, e.g. PMM_P as below

    and I don't know what to do with the PWM_M signal, connect it to ground or use a different filter design.

    And here I have a request for help in constructing an LPF to which I could connect two PWM_P and PWM_M signals

  • 0 in reply to Tomasz Pisarek
    TI__Guru**** 184576 points

    Hi,

    First of all, I have not much knowledge in this device. Is your question about TLV272? TLV272 simply has two OpAmp in it. I have shown you the functional block diagram of an OpAmp in the datasheet. It is just two instances of the same diagram. I'm not sure what schematic you are looking for. 

    The inputs to each TLV channel is a differential signals that come from TAS5508. 

    Tomasz Pisarek said:
    but in the documentation there is an example of LPF, where only one signal is supplied, e.g. PMM_P as below

    What documentation are you talking about?

    Tomasz Pisarek said:

    And here I have a request for help in constructing an LPF to which I could connect two PWM_P and PWM_M signals

    Where is this figure coming from? I don't find this figure in TAS and TLV datasheet. Or this is a generic LPF you are trying to construct out of TLV?

    As I have shown the schematic of the OpAmp for TLV as follows which is shown in the datasheet. This OpAmp will take the PWM_M and PWM_P (a differential pair) from the TAS. 

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Hi,

    Exactly, I need an electronic schematic of this element:

  • 0 in reply to Tomasz Pisarek
    TI__Guru**** 184576 points

    I don't think there is a detailed schematic for public but rather a generic functional diagram as presented in the datasheet. However, I will forward your post to the TLV forum team for comment. 

  • +1 in reply to Charles Tsai
    TI__Mastermind 30901 points

    Hello Tomasz,

    I believe the schematic that is posted in the datasheet just created a symbol to connect to a different schematic page. The inner schematic of the TLV272 will not be helpful here.

    I believe you are looking for the configuration of the low-pass filter that has been implemented. Unfortunately I couldn't find any documentation to how the authors of this schematic example have configured their circuit. Charles has linked a low-pass filter schematic from the TLV272 datasheet, and assuming the standard audio range to 20kHz, this filter could work. It is targeting 50kHz, but with some tolerance and some cushion to stay away from your cutoff frequency to maintain gain flatness over your passband, this may be an acceptable implementation.

    This seems to be a trend in older documents where a brief description was given, a hand was waved, and the assumption was that the reader was supposed to just "figure it out" which is not particularly useful when trying to build understanding.

    Best,
    Jerry

  • 0 in reply to Gerasimos Madalvanos
    Prodigy 10 points

    Hi Jerry,
    Thanks a lot for your reply, I have more or less understood the subject. I have installed PSpice, I will build LPF and do some tests, I hope it will work :).
    Thanks for your help guys.

    Regards,

    Tom

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Charles, 

    Thanks a lot for your help.

    Regards, Tom