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DRV8424: External Capacitors

Zeming Kong
Expert 3515 points
Part Number: DRV8424

Hi team,

Please let me confirm 2 questions about external capacitors:

1. X7R capacitors: Can X6S capacitors be used if the operation temperature is not so high?

2. Bulk capacitor: Do you have a recommended value? I found 100uF AL capacitor is used on EVM, can ceramic capacitor be used?

Best,
Zeming

  • +1
    TI__Guru 56650 points

    Zeming,

    1. Yes. X6S capacitors can be used if the operation temperature is not so high.

    2. The bulk capacitor can absorb the sending back energy from the load:

    a. the motor is driven by other source and is turned into a generator that pushes the input voltage high.

    b. suddenly brake the motor, the motor coil current has a spike and sends the current back to the input. 

    Using ceramic capacitor as the input bulk capacitor is OK to me. But, it would cost more for customers. Specially, the capacitance of ceramic capacitor would drop a lot when the input voltage is applied on it.

    Regards,

    Wang Li

  • 0 in reply to Wang5577
    TI__Expert 3515 points

    Thank you very much!