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BQ25756EVM: Gate resistors appear missing?

Part Number: BQ25756EVM

Tool/software:

I'm reviewing the eval kit schematic and layout, and the schematic clearly shows 0ohm gate resistors as placeholders to later tune in order to minimize gate ringing.

However when I look at the layout I can't find these resistors at all, either in the eval guide layout single layer views or on images of the physical eval board.

Were these omitted from the final layout?

If I intend to add them to my design am I correct in thinking I should locate them close to the gate drive pins as opposed to closer to the FETs?

  • Hi,

    The resistors (R3, R8, R17, and R20) are on the bottom of the EVM underneath the transistors. I am not aware of them being omitted in a refresh of the EVM. If you cannot find them, please send me a picture of the underside of your EVM.

    If including the strength limiting resistors in your design, placing them close to the FETs should be fine. There are more important considerations that should have priority closer to the IC. Make sure to keep the gate drive traces that they are located on short so that the loop inductance is minimized.

    Best,
    Michael

  • Thanks Michael, I'm just going by the documentation right now, not a physical board, and wasn't able to find them. 

    The eval board user guide does not have bottom overlay, and there is no picture of the bottom side of the board so it's difficult to know that there are components. 

  • Hi,

    That makes sense. I have pointed out the locations of the resistors on this image for your reference. Let me know if you have any more questions.

    Best,
    Michael

  • Much appreciated!