• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 29 subscribers
  • Views 627 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PCM5102A: Capacitor connected with VREG

Ryo Akashi
Genius 9470 points
Part Number: PCM5102A

Hello experts,

I have question about capacitor connected with VREG.
In datasheet, the capacitor value is 2.2uF, but customer want to use smaller value capacitor.
Is there any possible problem by using smaller capacitor value?

Thanks and best regards,
Ryo Akashi
  • 0
    TI__Guru 53923 points

    Hi Akashi,

    I do not recommend using a smaller capacitor here.  This is the output of the charge-pump and must be able to source all the current for the negative supply.  Note that this cap can be a ceramic capacitor.

    Thanks,

    Paul

  • 0 in reply to Paul_Frost
    TI__Genius 9470 points

    Hello Paul-san,

    Thank you for your reply.
    I understand it might be difficult to source all the current for the negative supply If we use small capacitor.

    Let me ask about charge pump circuit role.
    Is this charge pump circuit related with directpath technology(ground centered output like in below?)?
    If so, there is possibility not to make correct negative voltage due to small capacitor.
    Is my understanding correct?
    If my understanding is wrong, could you tell me the detail of impact of small capacitor?

    I would appreciate if you would give me reply. 

    Thanks and best regards,
    Ryo Akashi
  • 0 in reply to Ryo Akashi
    TI__Guru 53923 points

    Hi Akashi-san,

    You are correct.  The charge pump provides the voltage rail for the output amplifier.  Reducing the size of the capacitor on VNEG will reduce the total available charge for the output amplifier.  This will limit the output current capability and possibly lead to output clipping on the negative rail.

    Thanks,

    Paul