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TAS2505-Q1: Investigation of the cause of offset voltage occurring at SPKP/SPKM terminals

Ryota Seki
Prodigy 30 points

Part Number: TAS2505-Q1

Hello team,

The TAS2505-Q1 mounted on our board has stopped outputting sound at some point and continues to output a certain DC offset. Could you please tell us the possible cause of this problem?

 

The specific conditions are as follows

Output of SPKP and SPKM
SPKP: DC 1.2V
SPKM: DC 0.9V
The voltage on both pins remains unchanged at the above level even when input via I2S to play sound.

Short-circuited to GND
SPKM and GND terminals are shorted. approx. 0ohm
SPKP and GND terminals are not shorted. approx. 0.9kohm

The power supply voltage and its current
SPKVDD: 4.82V 1.4A
IOVDD: 3.14V 0.17A
AVDD: 1.76V 0.017A
DVDD: 1.75V 0.033A
*Currents are approximate.

Supplemental information
Both SPKP and SPKM are located on pins next to the 13V power supply on the connector.
We would appreciate it if you could let us know if this occurs when SPKP and SPKM are connected to the 13V power supply.

  • 0
    TI__Guru 57210 points

    Hi

    The absolutely max voltage on the OUT and SPKVDD to SPKVSS is only 6V. 13V power supply would very easily damage this device.

  • 0 in reply to Shadow He
    Prodigy 30 points

    Hello He-san,

    Thank you for answer.

    I understood if the OUT is shorted to 13V, the device will be damaged easily.

    Please let me ask additionaly. Can other causes lead to this symptom?

    This is additonal information.
    The symptom of no sound from the amplifier also occurred in the other unit.
    Although the voltages are different from previous unit, the situation is the same: DC voltage at both output terminals is being output and an offset voltage is being generated.

    Output of SPKP and SPKM
    SPKP: DC 0.059mV
    SPKM: DC 0.078mV
    The voltage on both pins remains unchanged at the above level even when input via I2S to play sound.

    Short-circuited to GND
    SPKM and GND terminals are shorted. approx. 0ohm
    SPKP and GND terminals are also shorted. approx. 0ohm

    The power supply voltage and its current
    SPKVDD: 4.9V 0A
    IOVDD: 3.23V 0.033A
    AVDD: 1.71V 0.050A
    DVDD: 1.74V 0A
    *Currents are approximate.

  • 0 in reply to Ryota Seki
    TI__Guru 57210 points

    Hi

    Ryota Seki said:
    Although the voltages are different from previous unit, the situation is the same: DC voltage at both output terminals is being output and an offset voltage is being generated.

    Is it permanent behavior, or Reset the device could make it normal?

    If it's permanent change, still indicates the damage.

  • 0 in reply to Shadow He
    Prodigy 30 points

    Hello He-san,

    Thank you for your continued support.

    > Is it permanent behavior, or Reset the device could make it normal?

    This is a permanent behavior.
    In both of these cases, the output pins and 13V may have been shorted in the test environment. Therefore, we would like to clarify that these two issues with some DC offset could be caused by a short circuit between the output pins and 13V.

  • 0 in reply to Ryota Seki
    TI__Guru 57210 points

    Hi 

    Ryota Seki said:
    we would like to clarify that these two issues with some DC offset could be caused by a short circuit between the output pins and 13V.

    Could be caused by a short circuit between the output pins and 13V, and create the damage.