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TLV320DAC3203 pops when DAC channels powerd up

Peter Pfeiffer
Prodigy 30 points
Other Parts Discussed in Thread: TLV320AIC3254EVM-K

I followed the example at page 74 of thenTLV320DAC3203 Applications Reference Guide.When sending the DAC power-up cmd (Page 0 Register 63 Value 0xd6) about 10 ms later a spike appears on the output lines. This happens regardless of how long I delay the power-up cmd (up to 10 sec). I also played with the page 1 register 20 settings, but this does not change the pop at the DAC power-up cmd.

How to avoid this pop ?


Best Regards

Peter

  • 0
    TI__Mastermind 46195 points

    Hi Peter,

    Power the HP outputs last. For the de-pop to work, you need to have a load reistance of low enough value to make the Rpop and Rload divider as low as possible. See page 17. If the load is too weak, then the initial spike will be too high.

    Regards,

    J-

  • 0 in reply to J-
    Prodigy 30 points

    Hi,

    I followed the advice to power the HP outputs last but nothing changed !

    I am using Rpop = 25K, N = 6, Softstep = 0, Rload = 32Ohm.

    With Rpop = 25K and Rload = 32Ohm, the very first power on pop low enough.

    But even if I leave the HP in mute, at that moment when the HP gain flags in page 1 register 63 bit 6 & 7

    are set (after about 5 seconds), a too loud pop occurs.

    Does someone overcone this pop problem. I would be glad to get a working  initialisation sequence.

    Best regards

    Peter

  • 0 in reply to Peter Pfeiffer
    TI__Mastermind 46195 points

    Hi Peter,

    Are you using a 47uF DC-blocking cap or something larger? The initial small pop is due to the resistor divider formed by the initial transient between Rpop and Rload.

    At the HPL or HPR pin, you can observe a cap charge waveform that lasts as a function of Rpop and the N value. The N time constant value assumes a 47uF cap is used for its internal calculations. With a scope connected to HPL and HPR, observe if the cap is fully charged before music starts playing after these 5 seconds or so. Actually, the N value could be set to 5 instead of 6 to reduce this time if you are using a 47uF cap or less.

    There is some small pop with this part. You can evaluate if it is acceptable using the TLV320AIC3254EVM-K and loading the High Performance Playback script for the AIC3254 CS software (which has a proper initialization sequence). This software can be downloaded from the EVM link above.

    Regards,

    J-