This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TAS5782M: Number of amps powered off PoE+

Part Number: TAS5782M

Hi there,

I'm hoping you can help point me in the right direction.  I'm trying to determine how many TAS5782M chips I can power (PVDD) using 802.3at PoE+.

As an example, assume I want to achieve the output power performance characterised on page 12 of the datasheet.  i.e. Stereo BTL mode using Test conditions:  VPVDD = 15 V, SPK_GAIN = 26 dB, RSPK = 4 Ω, THD+N = 0.1% to achieve an output power (per channel) of 23 W.

Can you please help me work out the answer?

Many thanks!

  • Hi Mark,

    According to the efficiency curve, the efficiency in the condition "VPVDD = 15 V, RSPK = 4 Ω, 23W*2CH" is ~87%(figure 33 on datasheet), then the total input power should be 46/0.87=~53W. Leaving 20% margin, it's suggested that the input power capability >65W.

    You may also check the input power by setting the device in this working situation to double check.

    BTW, usually audio amps needs a bulk input PVDD capacitance(like 220uF) to support audio peaks, not sure if this would cause any issue with your PoE application...

    Thanks!

    Regards,

    Sam

  • Many thanks, Sam.  That's a really god start, and like you say, I'll test out some!  :)

    Cheers,

    Mark