[dfox]

They are so popular that almost every linear-IC manufacturer manufactures something that is drop-in replacement for 7805 (and usually calls that 7805, although sometimes other part names are used, i.e. that "2805" on the die shot in article. I vaguely remember that NEC uPD2805 is 5V linear regulator with same pinout as 7805).

Between different manufacturers there is easily an 10x difference in price of 7805, so counterfeiting is certainly worthwhile, even more so when 7805 is more of a description of function than of implementation. 7805 means three-pin linear regulator with dropout <= 2V, such and such accuracy, line/load regulation and noise and typical design uses these parameters, not actual parameters guaranteed by given name-brand manufacturer (which are sometimes significantly better than for original LM7805), so mostly no-one will notice if you take random Chinese 7805 and repackage it into name-brand package.

[YZF]

It's probably <<10 cents in quantity though and most mass produced electronics would use something smaller or more efficient (well, it has to be more efficient if you want to go smaller) if they even use a linear regulator at all. What would the total world wide market for 7805 be today? A few million parts a year? As a counterfeiter you'd have a few % of that market? Maybe worthwhile as part of a larger counterfeiting operation if you have the flexibility to make a lot of different chips in a lot of different packages but investing a lot of engineering effort in this specific single chip is almost certainly not worthwhile.

[sitkack]

Why silkscreen your own brand when could silkscreen ST or National? I could move a whole lot more Nike than I could Mercury.

[kens]

I'd really like to know if you have info on a "2805" regulator. I couldn't find anything about a NEC uPD2805. All I could find is a NJM2805 regulator, but it's a totally different 5-pin regulator.

[dfox]

I will try to look into it more, but I too haven't been able to find anything conclusive.

What I know, is that about 5 years ago I have found part marked NEC uPD2805 (or maybe 2905) in power supply for Canon fax machine and somehow found out that it is 7805-esque voltage regulator and used it in my bench power supply as such.