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TAC5142: common-mode sense connection

Marvn Arcangel
Genius 16590 points

Part Number: TAC5142

Hi Experts,

I need help confirming the design below.

image (2).png

Im working on a project where I want to process FM radio audio digitally and mix it with other digital audio sources. To do this, I'm using an Si4703 (FM radio IC) and a TAC5142 (DAC). I want to use the plugged-in IEM/headphone cable as the RF antenna for the radio.

The TAC5142 uses a pseudo-differential output with an external common-mode sense. Normally, I would connect the common-mode sense directly to the GND sleeve of the headphone jack.

However, since I'm using the IEM cable as the RF antenna for the Si4703, I'm not sure how to properly make this connection.

I connect the OUT2M to the Headphone jack sleeve (CN1 pin 1) through a ferrite bead. The Si4703 FMIP pin is also connected to the ferrite bead. This should be correct right?

Thanks!

Marvin

  • 0
    TI__Mastermind 22246 points

    Hi Marvin, 

    In pseudo-differential mode, OUT1M outputs a common mode voltage sensed by OUT2M. This common mode is meant to act as the HP jack sleeve reference directly as you mention. Seems okay to me.

    I would double check with the SI4703 manufacturer to see if this is a valid connection with their part.

    Best,

    Garret