LinkSwitch-TN2 not working properly in Buck configuration

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We have designed a 5V buck based on DER-507( using LNK3206D.
But the output is 64V as opposed to 5V.
Circuit diagram attached. The HV+ and HV- is from a 120uF capacitor on a 100W TOP259 Flyback supply. We used ES1J(600V, 1A, 35ns) for both the diodes.
We have already tried swapping out LNK3206D(with that from a different vendor) and replacing 1.2mH general purpose axial inductor with 2mH Ferrite core inductor. All cases behaving in the same manner.
LED D51 not populated.

LNK3206_Buck.PDF18.81 KB

Never mind, it worked.

Hi PratyushJayachandran,

Apology for the late reply. Please let us know just in case you have further inquiries.

Thanks and Regards,

PI-Lupin the Third

Is SC1099 equivalent to LNK3206?
My local PI representative told us that SC1099 can be used instead of this but on reading the datasheet I found that SC1099 doesn't have any reference for operation on buck mode.
Is there some other inexpensive Semi Custom part or other series that I can use for Universal to 5V, 300mA, transformer less buck convertor?

Hi PratyushJayachandran

Good Day!

For input 85Vac - 265Vac and 5Vo with 300mA load Buck topology application, LNK3206 is suited for this application. I suggest that you use the standard Power Integration part.

You can register and use the Online PIExpert to compute for the design circuit values.

Application note for LNK TN2 is AN70.