Can exist different pinout for a transistor with same part number?

Discussion in 'General Electronics Chat' started by ranatungawk, Nov 6, 2014.

  1. ranatungawk

    Thread Starter Senior Member

    Oct 30, 2008
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    I found very common two 13001 switching transistors with different pinout. One is MJE13001 and the other one is 13001S6B. the pinout of MJE13001 ( L to R) is B-C-E but the pinout of 13001S6B is E-C-B. is this common ?
     
  2. t_n_k

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    Mar 6, 2009
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    Yes definitely possible. US & Japanese have different pinouts for TO-92.
     
  3. ErnieM

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    Apr 24, 2011
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    The last time I looked MJE13001 and 13001S6B were not the same part number.
     
  4. ranatungawk

    Thread Starter Senior Member

    Oct 30, 2008
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    part number is : 13001.., MJE or S6B are manufacture's code ...correct ?
     
  5. Papabravo

    Expert

    Feb 24, 2006
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    There is no a priori reason why that should be the case. Why would you think that?
     
  6. Ramussons

    Active Member

    May 3, 2013
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    I don.t think there a standard other than dimensions and structure for casings.
    A BC series has E-B-C, a BF series has B-E-C; both BC and BF are European standards.
     
  7. Stuntman

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    Mar 28, 2011
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    Easy mistake to make, there are a slew of parts that have consistent numberings but different suffixes/prefixes that have nothing to do with pinout. However, realize these often mean something other than just who produced them. If I were to claim some sort of loose rule, aside from the practical part number (ie 7905, or 1n4001), the prefix is often added to designate manufacturer, and the suffix can have any number of implications from packaging, materials, and even operational constraints (temperature range, voltage range, etc.)

    Not too long ago I was throwing together a test circuit and grabbed an NPN from my box, a P2N2222a. In my haste, I grabbed the datasheet for a PN2222. Spoiler: Collector and Emitter are backwards. It took a couple smoked parts for me to realize my error.

    Still yet, I have to wonder why the industry standard components and cases (like an NPN TO-92) wouldn't have standard pinouts. Perhaps the ending of the last paragraph is exactly that reason.
     
  8. ian field

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    Oct 27, 2012
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    As someone else stated; Japanese transistor pinouts usually differ from EU & US types - parts with the same number can sometimes differ from different manufacturers (mostly TO92 types).

    Usually the TO126 & TO220 types are standardised - but I have seen the occasional exception!

    VHF & UHF TO126 & TO220 types are usually different too.
     
  9. #12

    Expert

    Nov 30, 2010
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    The only cure is to go through the work of finding the exactly correct datasheet for every part before you design the circuit board. Sometimes a reversed emitter and collector will be a welcome simplification of the layout. Sometimes, you just get burnt fingers.
     
  10. ian field

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    Oct 27, 2012
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    Its worth remembering that most transistors exhibit a reverse B/E zener effect very substantially lower than the collector breakdown voltage.

    Its easy to identify the base by the apparent back to back diode analogy - once you have the base, its easy to tell C & E apart.

    Just remember to limit the test current to a low value.
     
  11. flat5

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    Nov 13, 2008
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    Glad I read this thread.
     
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  12. ian field

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    It may also be worth mentioning that some manufacturers offered a choice of pin layout for the basic part, perhaps the most common being the European EBC layout, and anything with an L suffix has the BCE layout of Asian transistors.

    I vaguely remember TI introducing the Silect family about late 60s/early 70s which were distinguished by the L suffix on some parts - unfortunately, not every manufacturer used the same codes.
     
  13. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Surely the reason is obvious?

    It allowed less complicated (more efficient) circuit track topology in the days before multiplane boards and routing programs.

    Many popular transistors were produced in a range of pinouts, including power types as well as small signal.

    Some manufacturers used letter suffixes to identify these, some used different type numbers.

    The moral is to always check your supply.
     
  14. flat5

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  15. ian field

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    The one I have is the Peak Atlas tester, anything that looks like 2 back to back diodes gets tested both ways round for gain to differentiate C/E.

    I've heard since I bought that; they've released a new super-duper version - there was some mention of a USB port and curve tracing.
     
  16. flat5

    Active Member

    Nov 13, 2008
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    Curve tracing is interesting.


    Peak Atlas DCA Pro - Advanced Semiconductor Component Analyser (Model DCA75)
    Official Video



    USB connection starts at ~15:28

    He loves to tell us which color connector is connected to which lead for every component tested. That drove me crazy :)

    http://www.peakelec.co.uk/acatalog/dca75-dca-pro.html
     
    Last edited: Nov 9, 2014
  17. ian field

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    Purely guesswork on my part; the European and many US transistors EBC layout may have evolved from the original alloy-diffused transistors - a slice of germanium as the base in the middle with a bead of indium melted into each side to form the emitter and collector - the early Japanese 2SA and 2SB germanium transistors also had the familiar EBC layout.

    When plastic encapsulation came along, the European and some US manufacturers maintained the familiar EBC layout. Asian manufacturers favoured the BCE layout - again purely guesswork; I suspect they put the collector lead in the middle to maximise the lump of copper the die is attached to, this results in a slightly lower thermal resistance than if the collector lead in the lead frame has to turn a corner to get to the die.
     
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  18. Stuntman

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    Mar 28, 2011
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    I'm not sure I follow. I can't think of a TO-92 transistor I've ever used that didn't have the base on pin 2. Therefore, the only reversal could be the collector, and emitter. This same reversal could be made by simply turning the part's silkscreen around. I'm not seeing the obvious simplification.
     
  19. bertus

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    Apr 5, 2008
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  20. ian field

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    Oct 27, 2012
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    Almost all Asian TO92 transistors have the base at one end an the collector in the middle.
     
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