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TAS5805M: TAS5805M - Low Pass Filter for PBTL

Part Number: TAS5805M

Dear Sir,

We are going to use TAS5805M in PBTL mode for subwoofer application.

We will be using the internal linkwitz-rilley digital filter to set the cut off frequency around 100~120Hz.

However, as the subwoofer will be 1.5~2m away from the TAS5805M, what do you suggest to reduce EMI?

1. Should/can we a need an external analog LPF to reduce EMI from the PWM signal?

2. If yes, what is the recommended component values for this analog LPF?

  • Hi,

              From my point, we don't need to add additional LFP behind the LC filter even the wire is 1.5~2m. Because the EMI of audio amplifiers are most caused by high frequency PWM switching, which can be eliminated by the output LC filter.  If you really find that the EMI is out of your expectation, you can try to add a RC snubber circuit in the wire. The value of RC should rely on the over point of EMI test result. In general 300pf+ 33ohm RC could be for your reference(Not the only value).