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DRV8833: How to decouple power supply for DRV8833

Francesco Mariottini
Prodigy 150 points
Part Number: DRV8833

Hello,

we are using DRV8833 motor driver to drive 3V DC gearmotor with typical current consumption of about 50mA. We would like to know if we must separate 3V power supply applied to VM pin of DRV8833 driver from other electronic parts as RF Bluetooth module, microcontroller, etc. that in this moment are powered with same 3V voltage. I know that when motor is running it put some noise on the 3V power supply line connected to VM pin by means of DRV8833 driver, is it sufficient put large ceramic capacitor (10uF typical) near VM pin of DRV8833 driver to mitigate this phenomena or is it better to use other electronic components (such as, LDO, DC/DC or some filters) interposed from 3V power supply and VM pin?

Many thanks in advance 

Francesco

  • 0
    TI__Guru** 114905 points
    Hi Francesco,

    In general, there is no need to separate the VM of the DRV8833 from the other electronics assuming there is enough capacitance to mitigate both positive and negative noise spikes on the 3V supply.

    The DRV8833 can survive noise spikes increasing the VM voltage up to 11V, but that may not be true of the rest of the circuitry.

    The DRV8833 can also continue operating down to 2.6V, but again that may not be true of the rest of the circuitry.

    One possible method to evaluate this is to separate the DRV8833 from the rest of the circuitry. A RC filter with a zener could be used to keep the voltage on the rest of the circuitry relatively stable. If you find the noise on the DRV8833 side is acceptable, the components can be left modified to reduce cost.