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I am using a TPA2005D1 With Vdd=3.3V and am looking for THD+N <=1% data for a 50 ohms speaker load

Darrell Davis1
Prodigy 10 points
Other Parts Discussed in Thread: LM48510, LM48556

My issue is that I would like to drive 144mW into my 50 ohm speaker and still be under THD+N <1%.  From what I can see the datasheet just does not have what I need to say this will work or not.  I tried extrapolating that data from the figures and its not looking good but it is close.

Has anyone had any experience driving a 50 ohms speaker from Vdd = 3.3V?  Will this work and meet my requirements?

Thanks,

  • 0
    TI__Guru**** 189401 points

    Hi, Darrell,

    Welcome to e2e, and thanks for your interest in our products.

    I looked at the d/s as well, and it seems like you don't have enough voltage to make 144 mW into 50 ohms. Do you have any flexibility on any of those three parameters?

    -d2

  • 0
    TI__Expert 3350 points

    Darrell,

    Based on V^2/R, the max power you can get into 50ohms with 3.3V is 108mW.  What you need is a device with a built-in boost to give the amp more headroom.  Take a look at the TPA2080/TPA2015/LM48510.  They do require an inductor, so the solution size increases, but that will get you to your output power target. 

    If you do not need to use Class D, another option, is the LM48556.  It uses a charge pump instead of a boost converter, gives you >200mW into 50hhms from 3.3V, but its a Class AB output stage, but its a smaller solution than the boosted amps.

    Regards,

    royce