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I have a question about LNK6664 Transformer Design.

Posted by: jason brody on Mon, 03/15/2021

I`m student developer that uses LNK series. And when I`m using LNK6664 to make 220->12V/2.5A AC/DC Flyback Converter, I got stuck with RM8 Transformer. I didn`t find any data about the transformer I have to wind, so I can`t even wind the transformer myself. Where can I find the information about that transformer?
I`m using it to power my 3w wireless router and 24w phone charger. And I`m developing this by myself.


Submitted by jason brody on Mon, 06/14/2021

In reply to by PI-Salt

I still don`t know about the open frame. of course, adapter means It has no ventilation hole nearby. However that`s not mean It doesn`t need a heatsink... When I see your referance, the heatsink is just an metal sheet...Is that mean when I have some ventilation hole, I can use 50X5mm heatsink and change product to 6665E?

Just to be sure, I uploaded my schematics, PI Expert Online and part of my PCB Design. I`ll definitly use 40x40mm ventilation hole, but I don`t think there is not enough space for cooling Fan. the White part on PCB Design is heatsink.

And one more thing. How do I put Heatsinks on inn3378 and inn3678 when they`re are on same PCB? Do I have to put a big heatsink? or I don`t need any of them? 

Submitted by PI-Salt on Tue, 06/22/2021

Hi Jason Brody,

Thank you for showing interest in Power Integrations and its products.

There are wide array of design you could look through since your specific design is only less than 30W. INN3378 and INN3678 doesn't need big heatsink unless you are operating at more than 65W output power. The good thing for InnoSwitch3-Family is its high power capability. 

Here is the link where you can already find solutions/designs that are similar to your specific design requirement:

You could filter/sort out the Inno3 products that I think suitable for your application. 


Lastly, I would like to suggest the following DERs that you might want to check: