Heat sink for 24v13 and 24v21 motor drivers

Hello,
Is it possible to attach a heat sink to 24v13 and 24v21 motor drivers using two screws and thermal paste?
Do you have any guidelines or recommendations on how to to that?
Especially, is it safe to have the components in the bottom of 24v21 surrounded by thermal paste?
Is insulation needed between the screws and the board as this is done for, say TO220 packages?
Thanks,
Best regards,
Georges.

Hello.

Yes, it’s possible to attach a heatsink as you are describing, but we do not have any specific guidelines or recommendations. It would be up to you to make sure not to short anything out, and we generally suspect thermal pads would be the safer/easier way to go over thermal paste, though we do not know about the relative performances as there are so many options for each. Regarding the questions about holes, if you are asking about the mounting holes, those are not electrically connected to anything. You can look and see how close the PCB traces get to those holes, and you of course have to make sure not to short any of those traces to anything.

Are you sure you even need a heatsink? And by the way, we have observed that forced airflow (e.g. from a fan) can be much more effective than a small heatsink with no airflow.

- Patrick

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Thanks for your reply.
I consider using these devices in RC model boats and while pushing them close to their current and voltage limits. They will be quite confined inside the hull with no easy way of having an air flow. My idea is to attach them to an aluminum plate (maybe 2 mm thick) placed at the bottom of the boat, directly in contact with water (where there should be some flow when the boat is moving) on the other side.
Assuming that the pictures are up to date, there is metal in the holes for 24v13 but not in those of 24v21. For the former, do you confirm that they are not connected or are they connected to GND?
In order to better evaluate the heat to be dissipated, can you tell me the value of the MOSFETs’ resistance in their ON state?
Georges.

The pictures are a little out of date; we do not plate the mounting holes now. However, I can confirm that in either case the holes are not connected to GND (or any other circuits on the board).

The on-resistance for the MOSFETs on all of our G2 High-Power Motor Drivers is on the scale of a few milliohms.

- Patrick

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