Tool/software:
Hello we are building a product with the TAS2563RPPT. We brought our product to an EMI test lab and found that when playing sound we experience large broadband noise from ~145MHz to 170MHz (see "sound_on_no_ferrites"). This noise goes away completely when sound is not playing.
We then spun our board to add 120ohm ferrites (PN = BLM15PX121SN1D) + 1nF capacitors to the speaker lines (see attached schematic). But we saw very little (2dB max) to no improvement.
Another experiment we tried was adding clip-on ferrites to the speaker wires them selves and that made a massive improvement, the entire broadband mountain went away.
We cannot implement clip-on ferrite beads in our design because of mechanical constraints. How can we fix this EMI issue using board level components or software (like spread spectrum)?
Sincerely,
Corey
