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DRV8842: the capacitor

K.Hamamoto
Guru 12155 points
Part Number: DRV8842

Hi

The customer concerns about the capacitor that is connected at CP1 and CP2 and VCP and V3P3OUT.

That is "How much max voltage should we estimate at the following capacitor?" and "How much capacitor is it acceptable for the capacitor? (+/- 50%? or less?)"

1. CP1 and CP2 : it should be VM voltage at least. And it need 0.01uF +/-50% accetable. (We need to consider DC bias specifications)

2. VCP : the charge pump voltag is ~11V. So that, 16V need at least. And 0.1uF +/-50% at least.

3. V3P3OUT: The internal LDO output is 3.3V. It is mentioned at datasheet as 0.47uF and 6.3V. Why does it need 6.3V? And how much does it need for this capacitor ? +/- 50% is needed ?

I referenced to the following post.

https://e2e.ti.com/support/motor-drivers/f/38/t/716344?tisearch=e2e-sitesearch&keymatch=DRV8818%20vgd

Best Regards,

Koji Hamamoto

  • 0
    TI__Guru** 114905 points
    Hi Hamamoto-san,

    1) Correct. The CP1/CP2 capacitor will have ~VM V across it.

    2) Correct. The VCP capacitor will have ~11V across it, but the voltage can be slightly higher.

    3) The V3P3OUT capacitor can have up to 3.6V across it. So a 6.3V capacitor was selected for extra margin. The voltage rating can be >6.3, but this may increase the cost. +/-50% is needed.

    I hope this answers your customer questions. Please let me know if you need clarifications.
  • 0 in reply to Rick Duncan
    Guru 12155 points
    Hi Rick-san,

    Thank you.

    Best Regards,
    Koji Hamamoto