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Extending LNK305 Buck input voltage - cascoded config

Posted by: MCsongor on Thu, 10/07/2021


the LNK305s input voltage can be extended by adding an external MOSFET in a cascode configuration, this is true in a Flyback. 

Is it possible to extend the input voltage range of the LNK305 with a similar solution in the buck topology?


Thanks and regards,



Submitted by PI-ZBDelta on Fri, 10/15/2021

Hi MCsongor,

Yes, it is possible.

You may look at DER-719Q (60Vdc-900Vdc input, 2.7 W output StackFET buck) as a reference.

It uses LinkSwitch-TN2 which has similar operation to LinkSwitch-TN but with added features such as BP/M pin shutdown function, Ilimit selection, and soft-start.