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DRV8842: Schematic Verification

Part Number: DRV8842

Hi,

I am trying to design hardware that can drive 2 motors, each drawing about 3 Amps, using 2xDRV8842. I've drawn the schematic and would like to get this verified. Can you please have a look and tell if there are any issue with this?

I also want to get the PCB to be "Boosterpack Compatible". It'd be of great help if you can confirm if everything is looking good.

Thanks

Download File.pdf

  • Hi Teja,

    The schematic looks good, although there are a couple of items to confirm:

    1) Are OUT2_1 and OUT2_2 connected? A connection dot is not shown.
    2) Are you planning to set the current at 3A by using I4:0? If not, you could have up to 5A.
    3) The fault LEDs connections do not look correct. Please double check them. It appears the LED will be on at all times.


    When creating the PCB layout, please look at the DRV8842EVM for a starting point. It is important to have a good thermal plane and local decoupling near the VM pins of the devices.
  • Hi Rick,

    Thanks for your inputs.

    1. Yes. OUT2_1 and OUT2_2 are to be shorted. I made the correction.

    2. By default, I set the current limit to 5A. But, I wanted to set the limit by SW. That's why I exposed the pins.

    3. Yeah. I was intending to connect the N side to pin. Thanks!

    I'd like this PCB to be Boosterpack compatible. Can you also have a quick look and see if anything doesn't look right for the board to be boosterpack compatible? Do you think we shall have decent thermal plane if the form factor(Boosterpack) is small(We've 2 drivers, each driving 3A current at 12VDC, in the design)

    Thanks

  • Hi Teja,

    In addition to the size of the PCB, thermal perfomance depends on the size of the thermal plane, number of layers, copper thickness, and ambient temperature.

    Do you plan to run the both drivers at 3A at the same time?

    Will the drivers operate at 3A all the time, or only during brief periods?

    Please take a look at the DRV8842EVM as an example of how the devices can be routed. On the EVM you will notice large ground pours for thermal.

  • Hi Rick,

    Thanks for the response. Yes, the motors will require 3A continuously.

    I shall have a look at the EVM.

    Thanks