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TLV320AIC3256: TLV320AIC326 Temperature change causing MIC_detect issue.

Part Number: TLV320AIC3256

Hi Team,

My customer is running into a problem where MIC_Detect fluctuates without unplugging the MIC when the ambient temperature changes from 25C to -40C and -40C to 25C( they said the problem is easily reproduced when they open the door of the chamber when it's -40C)

We can see from the waveform the TIP1 is always low and the MIC_Detect jumps.

Have we seen this issue before?

  • Hi,

    Few things to check:

    • Does this correlate with the flag (page 0 Reg 44) or interrupt when it happens? It could be just the sensitivity of the probe itself.
    • If the detection is real, have they tried with different debounce time? This setting is available in page 0 Reg 67.
    • Can they move the probe outside the chamber for probing if it's inside currently?

    What is TIP1?


  • Hi,

    Customer wants to know the following:

    1. How does Audio codec IC detect the AMIC plug in/out?
    2. Does any chances to fine tune this detection, for example, detection values, hysteresis… etc.
  • Hi,

    1. This is basically measuring DC resistance between the microphone pin and ground, a voltage divider with the Mic Bias resistor.

    2. Have they tried with the debounce time?


  • Hi Team,

    It seems like the root cause was the MIC resistance changes during drastic temperature changes.

    Customer has another questions about the supply voltages:

    In the datasheet, it mention that “Vsys must always be greater than or equal to Avdd and Dvdd”.

    Does“Dvdd” mentioned here include DRVdd_HP? or it just means pin 40?

     In their design, DRVDD_HP = 3.3V, AVDD=1.8V, VSYS = 1.8V.   which gives VSYS < DRVDD_HP


     Please kindly provide your comment thanks!

  • HI,

    Good to know.

    Just DVDD and AVDD.