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DRV8343-Q1: Bypass Capacitors on VM Pin

Part Number: DRV8343-Q1

Hello,

DRV8343S-Q1's data sheet recommends a set of bypass capacitors of 0.1 µF, 4.7 µF, and > 10 µF in Table 36. External Components, but I'm wondering if the > 10-µF electrolytic capacitor can be removed or not. Could you give me guidelines on whether to add or remove these bypass capacitors, especially, the > 10-µF electrolytic one?

Best regards,
Shinichi Yokota

  • Hi Yokota-san,

    The bypass capacitors are to help mitigate transients at VM if there are any excessive current demand requirements or generated voltages. It depends on the motor current used, motor braking/starting, supply inductance, motor inductance, etc. 

    We recommend at least 10uF bypass capacitance on VM to support any transients that may appear from motor current demands. Engineers will have supply bulk capacitance in the 100's of uF depending on how much motor current is required, but supply inductance (wires, PCB layout) can cause more transients at VM so we recommend the minimum bulk and bypass caps to mitigate any transients and ensure VM does not exceed the absolutte maximum rating. 

    Thanks,
    Aaron