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Original question:

DRV8306: DVDD [PIN 26] of DRV8306HRSMT is showing 4.2 to 4.8V

DRV8306: Schematic & Layout Review

Shivam Khole
Prodigy 50 points
Part Number: DRV8306

This question is related to DRV8306: DVDD [PIN 26] of DRV8306HRSMT is showing 4.2 to 4.8V.

Despite of all attempts, when we were unable to solve the issue - we suspected random issue & discarded the board.

And created a fresh version of board.

Please refer attached latest schematic & sectional layout of DRV8306.

The time - we have directly edited the TI' ref design as per our need.

Please review it & suggest if anything wrong.

We wanted to get an expert advise before board manufacturing - as our last attempt was not successful.


1031.TI.pdf


2475.DRIVER_CARD_V1.0.pdf

  • 0
    TI__Mastermind 23910 points

    Hi Shivam,

    We will need some time to review the layout and schematic. We will aim to provide feedback next week. 

    Regards,

    Joshua

  • 0 in reply to Joshua Horlander Cruz
    TI__Mastermind 23910 points

    Hi Shivam,

    To start, we do not believe that the DVDD you have been experiencing is related to layout. We noticed that in the previous two threads the debug steps were not completed so currently it is hard to determine the root cause of the DVDD issue. 

    There are some questions we have about the schematic/layout, would you mind answering them?

    1. What is the expected peak motor current of the system?
    2. What is the purpose of Inductors L4,L5, and L6?
    3. Would you mind providing the full schematic and layout?
    4. Could you provide the model of MOSFET you are using in your system?
    5. Could you provide the datasheet for the motor you are using?

    Our comments on the schematic/layout:

    1. The 51 Ohm gate resistance you are using is a bit high. We recommend lowering the gate drive strength setting being used and also lowering the gate resistance value.
    2. Since the datasheet recommends having >= 10uF bulk capacitance on the VM pin near the device, we recommend adding at least a 10uF cap to the VM pin
    3. There are points where high current paths have only one via, such as the CSA traces. we recommend adding more vias to these paths to help improve inductance.

    Regards,

    Joshua