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Original question:

TLV320DAC3100: Beep generator, MCLK waveform and Analog output waveform

TLV320DAC3100: Check if the SPKP/SPKM outputs are normal

Tyrone Liu
Prodigy 200 points
Part Number: TLV320DAC3100

hello

I have some questions similar as below.

https://e2e.ti.com/support/audio/f/6/t/833136?tisearch=e2e-sitesearch&keymatch=TLV320DAC3100

input clk/pwr to TLV320

MCLK  12Mhz

DVDD 1.8V

IOVDD 3.3V

AVDD   3.3V

SPVDD 5.0V

Circuits on SPKP/SPKM lines(Refer to TI application report SLAA581)

Series Bead(120 Ohm-100Mhz, 50m Ohm DCR) and parallel capacitor(470pF), respectively.

TLV320 registers configuration

 /cfs-file/__key/communityserver-discussions-components-files/6/4760.Audio_5F00_LP1_5F00_Register.txt

When speaker(8 Ohm) is working, I measured some waveforms as followings

Fig#1 SPKM(Speakerout-) overshoot voltage and ring voltage

Fig#2 SPKM(Speakerout-) ring current

My questions are

1. regarding Fig#1, if the overshoot(about 1.7V) will cause damage to TLV320?

2. regarding Fig#1 and Fig#2, are the ring voltage and ring current normal?

3. I have observed that no matter what sound is played, the frequency of SPKM/SPKP output remains around 300KHz, is it normal?

Thanks and best regards

TC Liu

  • 0
    TI__Guru* 84915 points

    Hi, TC Liu,

    Please take a look at my answers below and let me know if you have additional questions or comments.

    1. regarding Fig#1, if the overshoot(about 1.7V) will cause damage to TLV320?

    There's no risk of damage due to this overshoot. Usually our Class-D devices have this kind of behavior in order to reach the output level fast. Since the Class-D switches at high frequency, the device requires of this overshoot to set the output voltage.

    2. regarding Fig#1 and Fig#2, are the ring voltage and ring current normal?

    I don't see any issue on the output current. The current basically needs of this oscillation since the output is always switching. It cannot be completely flat since the output is not a constant DC level.

    3. I have observed that no matter what sound is played, the frequency of SPKM/SPKP output remains around 300KHz, is it normal?

    Yes, this is normal. The TLV320DAC3100 Class-D switches around this frequency.

    Best regards,
    Luis Fernando Rodríguez S.

  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 200 points

    hi, Luis

    it's clear enough and thanks a lot!

    BR 

    TC Liu