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TPA2012D2: output power at 3.3V

Part Number: TPA2012D2

Hi,

I can see the various output power with different VDD from Figure 33. Output Power vs Load Resistance.

but i need to estimate the outpower power level at 3.3V to insure output power from TPA2012 is not bigger than 0.7W speaker.

my speaker has 0.7watt rating thus i want to feed less than 0.7W to prevent blowing speaker.

where i can find the equation to calculate?

• Hi Wonho,

What is the impedance of your speaker?
The output power can be adjusted by changing the gain of the amplifier, or adjusting the input signal.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

• Hi, Ivan

My speaker has 8 ohms.

And, I want to set the highest gain (G0.G1=0) and insure output power from TPA2012D2 is not more than 0.7Watt by limitation of VDD.

is three any formulation to calculate this?

I think I am asking the same question twice.

• Wonho,

If you limit the output power by reducing VDD the output will be distorted. By lowering VDD the output signal will be clipped, if the gain is high the amplifier will still try to output the amplified signal, but if there is not enough voltage on VDD the signal at the output will be saturated.

I would recommend to either test your maximum input signal across different gain levels to verify that 0.7W is not surpassed, or adjust the input signal amplitude on a specific gain level. These two options would help to not saturate the output signal.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

• Hi, Ivan

what I wanted is how to calculate the maximum output power with 3.3V.

• VDD = 3.3V and gain = 24dB:

• Pout = 472.5mW into 8ohms @THD+N = 1%.Input = sine 128mVrms
• Pout = 573.9mW into 8ohms @THD+N = 10%.Input = sine 152mVrms

Below is a THD+N vs Pout plot for your reference.

You can calculate the output power like any other Class-D amplifier, and you can also use the TINA model to simulate the device on your required setup.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators

• OK, thank you

thus anyway less than 600mW in worst case, is that correct?

• That is correct, for you specific VDD and load impedance conditions.
Keep in mind that the input signal should be less than 152mVrms to keep distortion below 10% at gain = 24dB.

Best regards,
-Ivan Salazar
Applications Engineer - Low Power Audio & Actuators