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TLV320AIC3204EVM-K: The C34 cap of HPVDD input must be 22uF?

Part Number: TLV320AIC3204EVM-K
Other Parts Discussed in Thread: TLV320AIC3204

Dear all

      The C34 cap of  HPVDD input must be 22uF? I take the C34 cap with 10uF, theTLV320AIC3204 device will need 400mA current, and can't work any more. Why?

  • Hi, Went,

    The use of a 10µF instead of 22µF on the HPVDD source should not cause damage to the device.  Can you please provide more details about this issue?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • Dear Diego

         My issue is:

        When C501=10uF,C504=10uF, afrer 7.5V power on,the TLV320AIC3204 work normally, the current of main board is 0.1A;

        When C501=2.2uF,C504=0, afrer 7.5V power on,the TLV320AIC3204 can't work,and the device is very hot, check the current of main board, is up to 0.5A,but the normal current is 0.1A.

        please help me check the schematic,Why the TLV320AIC3204 can't work in only 2.2uF

  • Hi, Went,

    Thanks for the additional information. This is not a normal behavior for this device, but it is possible that the voltage on the HPVDD pin  is being affected somehow by the lack of the 10µF bulk cap on the pin. We recommend to keep the 10µF cap close to HPVDD pin in parallel with 0.1µF cap, is there any reason for you to not use it?.

    Do you have any capture of HPVDD pin voltage under both cases (with and without 10µF cap)?.

    Also, you mention 7.5V power on, what is this voltage?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • Dear Diego

           1. In mass production,  I use C501=10uF,C504=10uF,but there is also similar problem, the probability is very low more. I think C504=10uF is too small ? The EVM is set 20uF. Do I increase to 20uF, make sure it doesn't happen ?

           2. I test the waveform of HPVDD pin voltage, is good,like this

           3. The first voltage is 7.5V, through DC-DC bucking 3.6V, then through LDO bucking 3.3V, supply for TLV320AIC3204.

  • Hi, Went,

    Thanks for the feedback. The behavior you are observing is not common for this device and should not be expected. The decoupling cap, either 10µF or 20µF, should not cause issues on the device. The value selection for it depends more on the power supply quality, in the EVM we put a 20µF cap to make sure the EVM works well even with poorly designed sources.

    After looking the scope captures, I noticed there is step on HPVDD, which may be result of the 3.3V LDO being activated before 3.6V input supply is  stable. I am not sure if that could be a problem as it is not a recommended sequence.

    I noticed as well that RESET is connected to HPVDD pin, so maybe the part is trying to get out of RESET state before 3.3V supply is stable. We recommend to keep RESET in low state until all the supplies are valid. Can you please check that this condition is met in your system?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • Dear  Diego

           Thanks your analysis.

           In the datasheet, I can't find that the recommended sequence of reset with HPVDD power on.

  • Hi, Went,

    It is not reflected on the datasheet, but keeping RESET inn low state is a typical recommendation for almost all our devices.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer