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Flateric wrote:But they still get hot and need to be cooled correct? With some type of miniture Aluminium block or actively with a fan of some kind? Just to be sure you do not get cut out?

I have little heat sinks on mine, never have put a fan on em. Now the Rambo I have a fan on just because it's not out in the open.

Polygonhell wrote:The drivers are designed to shed heat from the back side of the device, the intent being that a copper pad is placed on the board itself to act as a small heatsink, I suspect that Rambo is in a better position with this than the pololu daughter boards if for no other reason than there is no airflow under the daughter boards.

SureSteppr daughterboards from Panucatt.com are better, IMHO.

SureStepprs are Pololu-compatible, but mount the chips on the underside so a heatsink on the top side will actually cool the chip. Recent SureSteppers also use a TI driver chip instead of the Allegro 49xx. The TI chips are less sensitive to stray voltage on the motor leads.

Just curious, how does a heat sink on the chip not a better way to cool a chip?

foshon wrote:Just curious, how does a heat sink on the chip not a better way to cool a chip?

Because the package is designed to be cooled from the bottom, not the top. Though, either way is not ideal because the sink isn't in direct contact with the surface designed to expel the heat.
It's spelled out in the data sheet.

I see.