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TPA3130D2: Control pins via 3.3V Logic

Muhammad Awais
Intellectual 720 points
Part Number: TPA3130D2
Other Parts Discussed in Thread: PCM5121, TAS5825M, TAS5805M

Hi, 

We are using TPA3130D2DAP in our design with 15V supply. We are using MCU 3.3V logic and we would like to control TPA3130 via 3.3V MCU IOs. Please answer the following to clarify;

1. I can see FAULTZ is open drain so we will add a pullup to 3.3V along with shorting it to the SDZ Pin. As per SDZ its TTL logic levels with compliance to AVCC. We will be using 15V to AVCC but as per recommended operating conditions SDZ pin VIN min is 2V so can you please confirm if we are good to go with connecting it to a 3.3V IO from the MCU?

2. Please confirm if same applied to MUTE pin by controlling it via 3.3V IO?

3. Can we control the volume for the audio amp via GAIN/SLV from 3.3V MCU IO? As per TPA3130 Eval board the design has pull-up at GAIN/SLV pin connected to the GVDD pin, same as per datasheet. Please note that we are using PCM5121PWR as Audio DAC before TP3130 so can we control the volume of PCM5121PWR instead of doing it for TPA3130? As per PCM5121PWR data we have Digital Volume control so I am assuming it will be done via I2C. Please confirm

Thanks

  • 0
    TI__Guru 52130 points

    Hi Muhammad

     For Q1 and Q2, since datasheet states the Min value of High-Level input is 2V, so using 3.3V from MCU technically should be no problem. 

     For Q3, not suggested to use IO control. The Gain setting only have very limited number of settings, if can't provide a correct voltage, may affect the final performance. PCM5121 is no problem to use I2C control Volume.

     And since we have digital audio signal in the system, and we are using PCM5121+TPA3130, how about consider using TAS5825M directly?  

  • 0 in reply to Shadow He
    Intellectual 720 points

    Hi Shadow,

    Thanks for clarifying on Q1 and Q2. 

    Actually right after PCM5121 we are adding TPA3130 but we also have to pass on the signal from PCM5121 to a FM transmitter along with TPA3130. Therefore we need to take out the Analog Audio signal from PCM5121. 

    By the way can you please suggest if we should use an op-amp as 2 separate buffers at the PCM5121 output so that one will connect to the input of TPA3130 and other buffer output to the input of FM transmitter to isolate both signals? I came to know that we can directly pass the DAC output multiple inputs but I think it will degrade the audio performance. Just for your reference our FM transmitter is a non-TI part, KT0803L. Please add your input on it, thanks.  

  • 0 in reply to Muhammad Awais
    TI__Guru 52130 points

    Hi Muhammad

       Technically the input should all be high impedance, so directly from DAC output to both device is possible. Just we don't have data about this using, especially for the characteristic of KT0803L, can't give you fully guarantee.

  • 0 in reply to Shadow He
    Intellectual 720 points

    Hi Shadow,

    Fine, I have added the unity gain buffer for both before going to the Audio Amp TPA3130 and FM transmitter along with option to bypass this Op-amp. Here is the snapshot along with color coding showing how the signals are going to both Audio amp and FM transmitter;

    Also, here is how the signal is coming out from the DAC;

  • 0 in reply to Muhammad Awais
    TI__Genius 15200 points

    Hello Muhammed,

    That seems appropriate. However instead of using the TPA3130 and the buffer, you could use TAS5805M and take the DSP/I2S input that the DAC is getting, might have some cost saving there.

    best regards,
    Luis