DRV8825 Being sold with the Pins facing in the wrong direction

Equipment: Arduino Uno + DRV8825 + Wantai Stepper Motor 42BYGHW811

I have noticed (through purchasing more than twice), that the DRV8825 stepper motor driver is being sold on ebay and other sites with the pins attached and facing the wrong direction.

What I mean by the wrong direction, is that if you were to attach the heat sink to the correct side of the board, the heat sink would get in the way between the driver and the bread board. So you have to remove the pins, and replace them facing the other direction, so that the heat sink can sit ONTOP of the driver, and not below it.

Here are some images to better explain this issue.

For example, take this image (often used to sell the piece):

The driver on the left is how people are selling it and this is incorrect. The driver on the right is how I think it should be, so that you can attach the heat sink to the top. You cannot attach the heat sink to the top of the left one.

I don’t understand why people are selling this driver with the pins attached in the wrong direction. It would help if people could become aware of this issue and maybe sell them with the pins not attached. But as far as I have seen, most of the drivers come assembled incorrectly. I have only found one seller selling them with pins unattached so far.

I would like to know if anyone else has encountered this same problem?, and if so, what do you do to correct the pins, without damaging the driver? (as I have tried de-soldering them, but now i think I have over heated the board because I can’t get it to work yet)?

Thank you for your time and consideration.

The Pololu engineers recommend the "wrong" way to solder the headers, for the following reason (described on their product page http://www.pololu.com/product/2133 )

Caution: Installing the header pins so that the silkscreen side is up and the components are down can limit the range of motion of the trimpot used to set the current limit. If you plan on installing the header pins in this orientation, please set the current limit before soldering in the pins.

You might post a question on the Pololu forum, asking about the effectiveness of installing a heat sink to that tab, versus other possibilities.

It is a matter of oppinion on how you mount the external heat sink. There is no right and wrong way to do this. Both options allow the heat sink to be on either side, a bottom mounting heat sink is harder to make but fine.
You can heat sink either side of the package, for sinking the top side use thermal conducting foam or gell.

Thank you jremington for pointing that out. Wrong assumption on my part. I guess that the first part I re-soldered doesn't work now because I didn't set the current limit before doing that.

I've just received a new one in the post again, and so Grumpy Mike suggests to use thermal conduction foam or gel to attach the heat sink to the top side. Do you mean the top, as the black part? And I have silicon heat sink plaster, will that also be ok to use?

Thank you both for your very helpful replies.

Hi, I think the SMT chip has an HEATSINK PAD on the base, thus we have an area of copper and vias on the reverse of the PCB. But if I saw this the first thing I would think is the silly *** as soldered the headers in up-side-down?? and I think I would solder it with components up top!

Regards

Mel.

The best thermal route is heatpad through the vias, since they are filled with
solder and conduct way better than the epoxy package. Ideally you’d use aluminium
substrate PCB for power devices like this and then the board is a heatsink itself.

However if you want to put a lot of current through a stepper you’ll always do better
with a discrete MOSFET design since the on-resistance of DMOS is much higher
than discrete mosfets. - Takes more components and board area, but generates
much less heat.

You can heat sink a component from any side, sure one side will be more efficient at getting the heat away but that is no reason not to use the other side. The heat sink paste is not so good for this it is the gel pad stuff that is much better although it can be expensive. I have used it to successfully keep the temprature down going from the plastic side.