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BUF634A: SPL 120dB using BUF634A on 8 ohm headset

Barry Klein
Prodigy 105 points

Part Number: BUF634A

I was curious to try using Google's Gemini AI to see what it would say for a headset application I have.

I also used several online Headphone requirements apps.

BUF634A to drive 8 ohm mono headset to 120dB worst case loudness, what power is necessary?

Assuming headset rating 100dB/mW.

Basically it/they came back saying:

Vrms .89

Current RMS 111.8 mA RMS

Power 100mW

My gut tells me I'm doing something wrong as the part is better intended to drive higher impedance headsets, not 8 ohm ones.  What's your take on it/

  • 0
    TI__Expert 4070 points

    Hi Barry,

    Let me look into this, will get back to you by Monday.

    Regards

    Anant 

  • 0 in reply to Anant Sinha
    TI__Expert 4070 points

    Hi Barry,

    The values looks correct to me.

    Since your headset rating 100dB/mW so for 120dB of loudness, you will require 100mW of power (100 time increase in power for +20dB increase in loudness).

    Vrms =sqrt(power x resistance) = sqrt(0.1x8) = ~0.894

    Irms= Vrms/resistance = 0.894/8 = 112mA.

    The device can support a continous 112mA of current, the power dissipation in this case from the device = 2V (output swing at this current level) * 0.112A = 0.224W.

    So BUF634A should be able to drive your 8ohm headset, you just need to look at the distortion number at these current and voltage level if that is ok for your application.

    Regards

    Anant

     

  • 0 in reply to Anant Sinha
    Intellectual 670 points

    I think the part I forgetting about was the power dissipation of the device (not the load) of about 2.5W.