Unmarked SO-8 package direction - LT1632

Discussion in 'General Electronics Chat' started by Veracohr, Jan 12, 2016.

  1. Veracohr

    Thread Starter Well-Known Member

    Jan 3, 2011
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    I have a couple of LT1632 in SO-8 package and they don't have a notch or any obvious mark to denote which end has pins 1 & 8. Would you assume the left side of this picture is pins 1 & 8?

    IMG_0590.jpg

    I soldered it to a DIP breakout board and connected the right-side amp (pins 5-7) as an inverting amplifier but saw only noise. I tried turning it around in case I was wrong but had no luck. When I turned it around again (back to the original orientation), I started getting a clean output signal but at unity gain when the gain should have been 3.7. Both amplifiers behave the same.

    I suppose I could have damaged it since one of the two ways I oriented it must have been wrong. I have another but I don't want to risk damaging it too not knowing how it should be oriented, otherwise that's $13+ down the drain. These things are pricey!

    And all this because I accidentally got the SO-8 version when I meant to get the DIP version. :rolleyes:
     
  2. Lestraveled

    Well-Known Member

    May 19, 2014
    1,957
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    Do you see the side that has the bevel? That is the side with pin 1. Look near the end of the data sheet at the package outlines.
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,070
    3,841

    Check the bevel

    image.jpg
     
  4. Veracohr

    Thread Starter Well-Known Member

    Jan 3, 2011
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    I did see that in the datasheet, and looked for it, but it seemed symmetrical to me. At a second look I can see it, although it's pretty subtle. The other side is definitely not as square as in the drawing.

    Thanks.
     
  5. SLK001

    Well-Known Member

    Nov 29, 2011
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    Isn't there a dot above the "3" on the top line?
     
  6. Veracohr

    Thread Starter Well-Known Member

    Jan 3, 2011
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    No, I think that's a blob of plastic or flux from soldering, and unfocused because I took the picture through a magnifying lens.
     
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