I saw this on a package drawing in a BC847 datasheet:

enter image description here

What do the numbers mean? They look like a date, but the SOT883 package is much more recent than 2003. (By the way, the numbers on the drawings for the other packages are "04-11-04", also palindromic. Coincidence?)

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    \$\begingroup\$ I'm voting to close this question as off-topic because it's not about EE. \$\endgroup\$
    – Andy aka
    Jun 13 '15 at 10:40
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    \$\begingroup\$ @Andyaka I disagree with you, it is an image taken from a transistor datasheet. How can physical transistor package outline drawings be off-topic? \$\endgroup\$
    – jippie
    Jun 13 '15 at 10:54
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    \$\begingroup\$ @Andyaka why is this not EE design related? Doesn't an electronics designer need to understand technical drawings of the parts he is using? By this argument an EE designer shouldn't mess with PCB fabrication tolerancing, for example. \$\endgroup\$ Jun 13 '15 at 10:55
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    \$\begingroup\$ @Andyaka (and the other voter-to-close): If you ever created a component footprint for a PCB package then you know that everything in a mechanical drawing is of importance. Since I didn't know what the numbers meant (that was my question!) I couldn't know if they're relevant. \$\endgroup\$ Jun 13 '15 at 11:49
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    \$\begingroup\$ I'm supportive of understanding everything in a datasheet. Too often something that will bite you hard is hidden in plain sight. \$\endgroup\$ Jun 13 '15 at 12:10

It is the drawing issue date in ISO order (YY-MM-DD). It's paired with the symbol for first angle orthographic projection, so obviously belongs in a title block of a full drawing. Below is part of a title block of a more complete NXP drawing.

enter image description here

Edit: as confirmation see the NXP package drawing, which bears the same April 3, 2003 date.

Edit2: The date format is specified to follow ISO order even in the ASME (U.S.) version of the GD&T standard as follows:

ASME Y14.100, 4.28: The method of specifying dates on drawings shall be numerical by year-month-day for entry in the “DATE” block. For example, June 10, 1989 would be indicated as 1989-06-10, 89-06-10, 19890610, 890610, 1989/06/10, or 89/06/10.

This is somewhat controversial (in the U.S. anyway).

  • \$\begingroup\$ +1: I think you are right. I had the same feeling. I recognized the European projection symbol (a.k.a. 1st angle projection symbol) and I was just searching for a confirmation of what meant the numbers besides it. \$\endgroup\$ Jun 13 '15 at 11:00
  • \$\begingroup\$ Yep, you are definitely right, as reported in this NXP drawing for the SOT883 package. At the end you can see the same issue date as the OP has on its datasheet. \$\endgroup\$ Jun 13 '15 at 11:07
  • \$\begingroup\$ So it seems to be a date after all. But how can we explain then that the drawing of a SOT883 is dated years before that package came into being? (Or am I wrong about the SOT883's date?) Thanks for your answer. \$\endgroup\$ Jun 13 '15 at 11:08
  • \$\begingroup\$ @JorisGroosman maybe an update to the industry standard is referenced. You may see in the link I posted in the above comment that updates are possible. \$\endgroup\$ Jun 13 '15 at 11:09
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    \$\begingroup\$ @JorisGroosman Oh, well, sorry then. I didn't notice the change. Your comment was indeed spot on. \$\endgroup\$ Jun 13 '15 at 22:57

Take a look at this random other datasheet page 9 which has some extra information with the symbols:

enter image description here

The taper indicates "European projection" and the numbers are simply a YY-MM-DD formatted issue date.

An alternative projection is "American projection". This Wikipedia article elaborates on the differences.

  • \$\begingroup\$ Same comment as for Spehro: So it seems to be a date after all. But how can we explain then that the drawing of a SOT883 is dated years before that package came into being? (Or am I wrong about the SOT883's date?) Thanks for your answer. \$\endgroup\$ Jun 13 '15 at 11:09
  • \$\begingroup\$ @JorisGroosman: nxp.com/packages/SOT883.html Don't know what date you had in mind. I didn't bother, but on the products tab you could check some other parts that come in the same package, and their datasheets which will probably be dated in turn... \$\endgroup\$
    – jippie
    Jun 13 '15 at 11:24
  • \$\begingroup\$ Just a nitpick: the date is NOT in ISO8601 format. That standard was introduced also to avoid most misunderstandings between date formats across different countries. That standard mandates a 4 digit year as it is also noted in the Wikipedia page you linked to. \$\endgroup\$ Jun 13 '15 at 12:03
  • \$\begingroup\$ @jippie: thanks for pointing out about the projection used, but that was not what my question was about (that part I did understand). Peace. \$\endgroup\$ Jun 13 '15 at 12:32
  • \$\begingroup\$ Can I have a TL;DR for the difference between the projections? (What actually differs) \$\endgroup\$
    – Alec Teal
    Jun 13 '15 at 13:29

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