How are MPNs chosen? Is there any guarantee of uniqueness?

[matthuszagh]

Do manufacturers of electronic components select their own part numbers (MPNs), or are these selected by an independent body? Is there any guarantee that part numbers are unique? If so, are there any permitted exceptions to uniqueness? For example, if I search 2N2484 on mouser I see a number of devices from different manufacturers with the same part number. In this case, I could see that it might be deemed permissible for different manufacturers to use the same part number if the datasheets specs are identical.

Actually, in the example I gave, it seems 2N2484 is covered by MIL-PRF-19500/376. So, maybe any components that meet those specs can be identified as 2N2484.

[TimFox]

The 2N- numbers were registered with JEDEC.
"JEDEC originally stood for Joint Electron Device Engineering Council, but it's now known as the JEDEC Solid State Technology Association."  (their website)
The registration includes a datasheet that parts with that exact number must meet.
This originated in the vacuum-tube days. "In 1924, the Radio Manufacturers Association (which later became the Electronic Industries Association) was established. In 1944, the Radio Manufacturers Association and the National Electronic Manufacturers Association established the Joint Electron Tube Engineering Council (JETEC), which was responsible for assigning and coordinating type numbers of electron tubes."  (ibid.)

[Konkedout]

I suspect that the JEDEC numbers are declining in use and importance.  I think that they apply only to discrete devices (not ICs).  Even among discrete semiconductors, I do not think that many new ones are getting JEDEC designations.  This means that companies are making their own part numbers.

When I was working recently for a military/aerospace company, we used some JEDEC designated discrete components but our ICs were not JEDEC.  I think we had some non-JEDEC discretes also...but my memory there is uncertain.

If I wanted to sell a semiconductor designated as Konkedout271B I do not think that anyone would stop me.

[ejeffrey]

Other than the 1N and 2N designations, many semiconductors have manufacturer prefixes such as LM, AD, TL, MC... This helped avoid accidental conflicts.  Of course consolidation in the semiconductor industry means most of those are now the same handful of companies, but they still often use the same designations based on the acquired teams and product lines.