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TLV320AIC3204: TLV320AIC3204 Line input maximum current

Jadran Surette
Prodigy 20 points
Part Number: TLV320AIC3204
Other Parts Discussed in Thread: LM6144, LM6142

We have a use case where there may be an input to IN1_L / IN1_R while the TLV320AIC3204 is unpowered. I'm assuming that there are TVS diodes on the line inputs to TLV320AIC3204 that will sink up to a certain amount of current, thereby protecting the device. We'd like to know if there are known absolute and recommended maximum current ratings for the IN#_L /IN#_R line inputs, as they don't appear to be listed in the data sheet or app notes.

Thanks!

  • 0
    TI__Guru* 84915 points
    Hello, Jadran,

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

    The current is limited by the AIC3204 input impedance and the absolute analog input voltage to ground (-0.3V to AVDD+0.3V). While the device doesn't reach these limits, there won't be risk to damage the device. So, the current would be limited from -30uA to 225uA (the input impedance can be adjusted as 10kohms, 20kohms and 40kohms).

    Additionally, we don't recommend to use the audio codec when it is unpowered. Since some input lines can be routed to the outputs, the input signal could be sent to the output line. In order to avoid these issues, we recommend to have the device powered up but in sleep or standby mode.

    For more information about these low consumption modes, please take a look at the document below:

    www.ti.com/.../slaa473b.pdf

    Best regards,
    Luis Fernando Rodríguez S.
  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 20 points

    Thanks for the response, but I'd like to clarify what I'm looking for. I'm not at liberty to be specific, but we have a scenario when a line level signal from an external product is transmitted to the product which contains this CODEC while the local power supply is disconnected (therefore, we can't keep it in low power mode to satisfy this use case). I'm aware that it's less than optimal to have an input to the CODEC while it's unpowered, and we'd prefer to disconnect the input from the CODEC via some sort of analog switch if we could make space for it on the board.

    So that said, the ESD diode should kick in while the CODEC is unpowered, and the current will sink through that like a short in order to prevent anything else in the CODEC from sinking current (assuming that there actually is an ESD diode, as "AVDD+0.3V" is usually an indication of a schottky). The current in the off state will therefore be the current rating of that ESD diode junction. A good example is the LM6142/LM6144 op amps that you produce. These rate the absolute maximum current at the input pin as +/- 10mA.Given that op-amp inputs are generally high impedance while on, then I'm assuming that this parameter is referring to the ESD diode current limit.

    So we're just wondering if you have a rating for this on the TLV320AIC3204.

  • 0 in reply to Jadran Surette
    TI__Guru* 84915 points
    Hi, Jadran,

    Thank you for this clarification.

    Unfortunately, the audio codecs maximum current rating is not specified in the datasheet. We only suggest to have the codec working under the recommended operating conditions. If the codec is not under these conditions, we cannot guarantee that it will work correctly.

    Best regards,
    Luis Fernando Rodríguez S.