Yet another stepper driver

YetAnotherStepperDriver is a breakout board for the DRV8825 stepper motor controller IC. The IC can put out 3A of current, so proper cooling is a must. This is the reason behind so many vias around the bottom pad of the IC.

These modules are designed to connect to a booster pack i have yet to design for a Stellaris Launchpad ( overkill? perhaps..) via the FFC on the left side of the board. The motor would be powered by 12V from a computer PSU via the screw terminals on the bottom. I tried to stay away from .1″ pins for the most part. I took inspiration from bearmos’ cnc controller with the thermal vias.

Via the forum.

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5 Comments

  1. Proper cooling is a must, but I see the power connector interfering with a properly sized heatsink, and no mating holes for such a heatsink.

    The smd chip has an exposed pad on the top, but this will require to mount the connectors on the bottom side, and the through-hole pins may have to cut very short.

    All in all, what lacks the most are mating holes.

    Here is a part of a design I made using a bigger Texas DRV8432: http://www.mirari.fr/Ik0h

  2. Yikes! only my second WIP version and already on the blog! At least it spurred some comments on the forum

    @openmakers: on the DRV8825 the exposed pad is on the bottom, hense the vias and fill under the chip. The heatsink is ment to be drilled/tapped to match the holes on the corners thermal tape is applied to the bottom side of the board under the IC and then the heat skink is attached to the bottom of the board (yes, with the through-hole pins cut as flushly as possible)


    __ _.---/^^IC^^\--._
    ==$==============$==board
    || **************** || thermal tape
    |||||||||||||||||||||||||||||||||||||||||||||||||||||

    1. Okay, got it ;) However I think that these sick of beige holes are spaced too far apart so the chip will not be correctly pressed on the heatsink surface, even if you’re using thermal tape. I would add a fifth hole near the center of the board, possibly at the right hand side of the chip, between the two inductors for example. Also, try to make the top power traces as wide as possible, because i doubt these tiny red things would carry 3 amperes of current witout blowing like a fuse ;) See my design picture, even if not perfect, you get the idea.

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