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Original question:

TAS2781EVM: TAS2781 Frequency Reponse of PWR_MODE3

TAS2781EVM: TAS2781 Frequency Reponse of PWR_MODE3_Part 2

Simon Yuh
Prodigy 100 points
Part Number: TAS2781EVM

HI sir

https://e2e.ti.com/support/audio-group/audio/f/audio-forum/1192735/tas2781evm-tas2781-frequency-reponse-of-pwr_mode3?tisearch=e2e-sitesearch

Sorry for replying late.

After I tried the procedure which Ivan provided. The result is as picture below, the red curve is the measurement with connecting “AUX-0025” filter.

But this result is not close to the TI spec, it dropped over -1dB before 40KHz.

If we measured without “AUX-0025” filter, the result became blue curve which is closer to the spec, but with worse THD+N.(following picture)

May I ask that what the method did you measure?

Is there anything I need to be aware of?

  • 0
    TI__Mastermind 18905 points

    Hi Simon, 

    AUX-0025 is a hardware low pass filter that will roll-off at 25kHz. 

    AUX-0040 is a hardware LPF which will roll off at 40kHz. this is intended for measuring Ultrasound >25kHz. 

    In the final measurement that Ivan shared he used the 40kHz version of this filter. this is why his measurement shows signal out to 40kHz. 

    Regards,

    Arthur