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TPA3118D2: SYNC

Part Number: TPA3118D2

hello to all,      

we are designing a dual mono amp based on  2 No's of TPA3118D2 chip. 

We have configured one chip is the master and another chip is  the slave by using SYNC signal in between them. 

In the slave mode, we are getting more THD+N compare to the master mode. ( Ex : THD+N ratio of  Master is 0.020879 % and Slave  is 0.158422 % with Po -1W)

 


1) Please advice how to reduce the THD+N in  the slave mode? And why we are getting more THD+N in the slave mode?

2) How synchronization will work between the master and slave?

thank you for assisting.

Andre

  • Hello Andre! Shawn can answer any further questions you may have, but as he is in China, time wise I'll start things out. I assume that you are running both amps in PBTL? What you likely have here is some excessive clock jitter in the system, based on either layout or grounding conditions, which is inducing the degradation. Please make sure that you have a very good ground between both devices. If this seems the case, then you may want to try adding a 10pf cap between Sync and ground.

    Shawn, Please feel free to add any other comments from your experience. Thanks, Jeff
  • Hi Andre,

    As Jeff explained, we need to check the hardware design at first. Please follow the reference design in Figure37 in TPA3118D2 datasheet. If you could show us your SCH and PCB layout, We can help to review the hardware design. Did yo measure the waveform on the SYNC pin on the slave device please? What about the signal integration? 

    THD measurement is a very sensitive test, please also make sure the GNDing between instruement and board/device is good. THD=0.02% looks a reasonable number, and 0.15% is not good. Could you double-check whether the two device are working in the same configuration/condition(except master/slave mode), e.g. PWM switching frequency, Modulation mode, input signal frequency,  Load resistance, Power supply...

    Best regards,

    Shawn Zheng

  • Jeff!

    glad to see our paths cross again.

    As always thank you for your support;  passed the info to our team and will hear back from them soon.

    regards

    Andre

  • Ni hao Shawn,

    xie xie for the reply, i am now waiting to hear back form my team.

    regards,
    Andre
  • Thanks Andre! And good to hear from you also. Shawn can follow up on any other questions you may have. Thanks, Jeff
  • Hi Andre,
    Is there any feedback for the team please? Please feel free to let us know if this issue is still not fixed.
    Best regards,
    Shawn Zheng
  • hello Shawn,

    thank you for your follow up.

    After changed the capacitor value from 1nf to 10pF (between SYNC and ground), the Master and slave modes are working fine.

    regards,

    Andre

  • Hi Andre,
    Thank you for the update. Gald to know that it's working, could you please help to close this question?
    Best regards,
    Shawn Zheng