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DRV8434S: External Capacitor values

Kei Kuwahara
Expert 7660 points
Part Number: DRV8434S

Tool/software:

Hello team,

I wonder should we consider DC bias for the values of the capacitors on Table 7-1?
If so, we should use larger capacitor values than listed on the table?

Also, CSW and CVCP is used for charge pump, so is it okay to ignore the DC bias?

Best Regards,
Kei Kuwahara

  • 0
    TI__Mastermind 19670 points

    Hi Kuwahara-san,

    I'm not sure I understand your concern with DC biasing. All values stated in the external components table are recommended for DC conditions. 

    Please elaborate on your concerns.

    Best,

    David

  • 0 in reply to David Medis
    TI__Expert 7660 points

    Hello David-san,

    I am sure you know this, but capacitors values decrease, when used in a DC conditions.

    All of our buck converter datasheet recommends to use larger capacitors values to compensate this decreased capacitance.

    Customer wants to know if they should do the same for DRV8434S?

    Best Regards,
    Kei Kuwahara

  • +1 in reply to Kei Kuwahara
    TI__Mastermind 44875 points

    Hi Kuwahara-san,

    For CSW the capacitor must be rated for VM. In this case you won't have to compensate with a larger value. If you use a much higher rating than VM then you may have to compensate for that.

    Likewise, for CVCP an X7R 0.22 uF 16V capacitor is suggested. You won't have to compensate this value with a larger value as long as you'd use a 16V rated capacitor.

    Regards, Murugavel