Unmarked SO-8 package direction - LT1632

Thread Starter

Veracohr

Joined Jan 3, 2011
720
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:
 

GopherT

Joined Nov 23, 2012
8,012
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?

View attachment 98519

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:

Check the bevel

image.jpg
 

Thread Starter

Veracohr

Joined Jan 3, 2011
720
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.
Check the bevel
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.
 

Thread Starter

Veracohr

Joined Jan 3, 2011
720
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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