>>>Possibly useless anecdote: I designed a buck converter based on the
>>>TL432. Regulation was "perfect" but efficiency wasn't so great.
>>>Extremely cheap I'd say.

>> I assume that you meant TL431 rather than TL432?

> "The TL432 has exactly the same functionality and electrical
> specifications as the TL431, but has different pinouts." =A0from
> http://www.ti.com/product/tl432

Worse!!!!
The TL431 and TL432 will often be pinout variants but some
manufacturers make a TL432 with a TL431 pinout.

Manufacturer and distributor must be specified and locked in with any
variation from this requiring change control and testing and
certification of the alternative. Enforcing that from a distance
without "being there" relies totally on integrity and buy-in and
competence of the manufacturer. That's an unrealistically large amount
to expect of a manufacturer in many cases.

Some years ago I saw (afterwards & from a distance) a complete
production  batch of products made and shipped with a pinout-incorrect
variant of the TL431 SOT-23 pkg installed.  These had a significantly
bad  effect on performance. and the factory engineers involved were
aware that performance was not as it should be but did not know why
and did not report it and afterwards justified it with an explanation
re how they thought that was what was wanted. Complete swapout of PCBs
or recall of that batch of product was required.


        Russell McMahon

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