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What is the difference between these parts? The datasheet shows completely different pinnings, but both are specified over the same range and both have the A, B and ungraded specifications for tolerance.

Just curious.

Thomas O
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From the datasheet:

The TL432 has exactly the same functionality and electrical specifications as the TL431, but has different pinouts for the DBV, DBZ, and PK packages.

endolith
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    Hmm interesting. Why would TI produce different pinned versions? Is it to ease routing on crowded PCBs? – Thomas O Oct 18 '10 at 21:44
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    I guess? Or maybe for compatibility with competing parts? – endolith Oct 18 '10 at 23:40
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    They probably redesigned the die, which caused the pin connections to move about. – Connor Wolf Oct 19 '10 at 06:56
  • I suppose they probably redesigned the die to reduce costs and/or increase yield, but couldn't make it pin-compatible. Maybe the TL432 is cheaper than the TL431. – Thomas O Oct 19 '10 at 11:49
  • TL431CDBVR and TL432CDBVR, for instance, are both $0.14 budgetary, so I don't think that's it. http://focus.ti.com/docs/prod/folders/print/tl431.html#pricingpackaging http://focus.ti.com/docs/prod/folders/print/tl432.html#pricingpackaging – endolith Oct 19 '10 at 14:37
  • Hardly any other part in the world is made by so many different companies as the 431. The differently pinned versions made by TI very likely reflect the fact that there are even some 431s out there (made by others than TI) that sell as 431s. I thin it's all about second sourcing and purchase departments constantly going for the cheapest option. By the way: I think that meanwhile the 431 outnumbers the 555. Just think about all the switchers for PCs, cell phones and the like. Most do use the 431. – zebonaut Oct 30 '10 at 10:11
  • @zebonaut - Why would you use a shunt regulator for a switcher? The chargers/adapters I've seen inside all had an MC34063. This has an on-chip reference, and is available in a 4mm x 4mm DFN package, so can be integrated easily in any product. – stevenvh Jul 24 '11 at 18:04
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    I should have said "isolated switchers", to be exact. Lots and lots of isolated switchers use a TL431 on the secondary side. Its output is transferred to the primary side via an optocoupler. This app'note shows a step-by-step explanation how the TL431 replaces the reference/feedback circuit of a switcher IC: http://www.national.com/an/AN/AN-1095.pdf Not that I think it's a particularly elegant solution, but it shows the general idea. – zebonaut Jul 25 '11 at 20:25