TPA6120A2: TPA6120A2 Power

Hi,

Welcome to e2e.
Do you have a more specific performance target? SPL would be sensitivity of the speaker or the perceived sound at a specific distance form the speaker.
TPA6120A2 is used on headphone applications so no actual distance to the speaker is present. Do you have another target spec, like output power?

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

Hi, Ivan. Thanks for supporting.

Yes, no distance needed (on ear). But max SPL obtained was 120 dB (32R ear speaker, SPL 110dB-1kHz/1Vrms) with +/-12V power supply.

I want to replace the current amplifier of an audiometer (use transistors) by a robust and integrated solution as TPA6120A2. I'll try put a extra output power block in series with TPA6120A2 based a standard class AB circuit. Have you a suggestion?

Thanks again.

Have you tried different gain? How was max SPL obtained (input signal voltage, gain)?
I assume that since the speaker spec is 110dB 1kHz/1Vrms and you obtain 120dB, the voltage at the speaker is a bit higher than 1Vrms?
I think that using +/-12V should allow higher output voltage than 1Vrms. If not tried before, perhaps increasing the gain of the amplifier could be an option.

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

Yes, I tried different gain. I obtained 125dB with 800 mV input voltage and gain 6V / V. Above this, signal is distorted.
I tried with TDH-39P ear speaker (10R, sensibility 108dB SPL 1mW/1Khz) and the result was more poor yet. Same input voltage and gain.

I keep making attempts here.

Best regards,

If audio is distorted at a certain point, I think it is getting clipped at the supply voltage.
Then I would try to increase the supply voltage. Increasing the supply voltage would increase the dynamic range for the output signal, letting you to output higher voltage amplitudes before distortion comes in. For supply voltage of +/-15V you would obtain an output voltage range of about 12.5V to -12.2V

What is the output voltage range you obtain on your test? Do you have captures of that?

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

Hi, Ivan.

One question: If I have 1V at input, I'll have 1V at output (TPA6120A 1V/V gain), right? Or not? Load 16R. Can you explain me?

The output is loaded down by the load impedance. The lower the impedance lower output voltage drive.
16-ohm load is the minimum specified so it presents the bigger load for the output of the device. Higher loads, like 600-ohm or 1k-ohm would provide a linear 1Vrms input vs 1Vrms output response.

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