Heatsink top270eg

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I have a casing that is very small made up of aluminum. I read in the manual that you should not ground the heatsink for the top270. I have a problem to fit a correct size of the heatsink and was thinking of using the case as a heatsink with  a 3mm aluminumoxide isolation. You think that will work or will there be a problem whit that? The case is grounded to protective earth.

Best Regards

Lasse Eriksson

Could you PLS tell me where you find the information? I mean heatsink can not be connected to primary side ground.




In the datasheet for the TopSwitch-jx i read in the datasheet.


To avoid circulating currents, a heat

sink attached to the exposed pad should not be electrically tied

to any primary ground/source nodes on the PC board.


Best Regards


Sorry for late response. I believe you can use the case as heatsink as long as you have insulations between the pad and the case. With the insulation,  you do not have to worry about the circulating current at all.