I am working on Lytswitch-5 base isolated design using 5216D. Circuit works properly with open enclosure. But when I mount in closed enclosure within 12 minutes it gets too much heat and gradully current decreases and then it shutdown. IC blown out by its Drain and source gets shorting when this problem occurs.
o/p voltage : 54V,
o/p Current : 290mA
Transformer Geometry : EE16
I request you to guide me to solve this problem.