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tlv 320aic3104 input from other mic in dual mic setup

rohith ram
Prodigy 60 points

Hi, 

I'm working on a setup wherein two (mic2l and mic2r) mic are connected to left adc.

When capturing sound with reg 17= 0x5f and reg 18 = 0xff   with no mic connected on mic2l and a mic on mic2r, I can still hear sound getting recorded on the microphone connected to mic2r, though low, it's clearly audible.

Also, instead of capture just did a bypass(register 46) to HPLOUT and the same behavior is seen.

Is there any steps to debug, fix this issue.

  • 0
    TI__Mastermind 28585 points

    Hi,

    This is most likely cross-talk. There are parasitic capacitance paths through the device that will cause some "leakage" between channels. This can be amplified by improper layout. Another place to watch is with the mic bias. If you are sharing a single mic bias with several mics, there is signal path between the two mics.

    The cross-talk within the converter itself will be bellow -60 dB and is usually not a big concern, if it is higher than that you should look at you layout and schematic. I can take a look if you want to attach them.

  • 0
    Prodigy 10 points

    I am wondering if you ever resolved this, and if so, how.  We are having problems with Line1R to MIC_3L crosstalk (on an AIC34) and wondered how you solved your problem.

  • 0 in reply to Mark Chambers1
    Prodigy 60 points

    Our requirements as of now doesn't need two MIC's and hence this issue became a low priority.

    I did try with changing the MICBIAS and finally we are using an external voltage source for biasing.