Today I received some LM399H, and to my surprise they came without the thermal shield:
I already contacted the vendor to return it.
Is there any reason to not return it, even if the seller offer a discount?
Very strange that the bare can IC is sold, I've never seen that before. The plastic cap is made of Polysulfone, VALOX
TM of General Electric, because the chip runs at 90°C, which lets most other plastics get brittle after short time. Therefore, 3D parts from random plastics will not work.
My only very old stock part looks like this. I assume from this old logo, that it is also from National semiconductor, bought from a regular distributor in between 1992 - 1995, don't remember any more the exact date.
I opened the plastic cap (broke a small edge off), and the metal can is completely blank, no imprint on the top, nothing on the side.
Maybe yours are fakes or rejected ones for both reasons, coming with no plastic cap (which is difficult to fake) and with an imprint.
Frank
PS: The old logo was changed in the era of CEO Gilbert F. Amelio, who took over in May 1991.