Heat sink requirments

Hi, Does Schottky diode MBR2X030A045 require a heat sink to operate at 50 amp continuously? If so, what size would be appropriate?

Welcome to the Digi-Key TechForum maddogmeade.
The datasheet shows it can handle an Average Forward current of 60A with a temperature of Tc=110C. So as long as it does not get hotter than that, you would be okay. Once it gets hotter, the current it can handle will drop off quickly.
A heatsink will help keep the temperature lower, and the larger the heatsink, the better it will transfer the heat.
I do not know what size heatsink would be recommended. Maybe one of the Engineers on the TechForum can add to this, and have some recommendations.

The forward voltage of that diode @ 50A is roughly 0.8V; the power lost is thus 0.8V*50A=40W. It’s a dual device, so if you’ve got 50A running through both, the figure would be double. If you’ve ever grabbed a 40W incandescent lamp that’s been running a while, you can appreciate that it’s a fair amount of heat to get rid of. So yes, a heat sink is in order.

This post describes the process of heat sink selection. Assuming that you’ve got a 40W thermal load, a heat sink with an effective thermal resistance of about 2°C/W or less would probably be a reasonable choice.

Hi Rick,

Can you suggest a product number that will match your advice below?

I’m having trouble finding a suitable sink.




Within the heat sink product family, the manufacturers’ estimated thermal resistance for the various products is shown under conditions of forced airflow and natural convection. One would typically start a search by selecting products having a thermal resistance value equal to or less than one’s target maximum value, from whichever of those two best represents the conditions of use.

Failing that, 125385 would likely be sufficient for the task.