Well, I have a 6-pin SOT23 and it is absolutely tiny. When I say tiny I mean it. Anyway, it is unclear which way it goes around as it has no indicator, so I don't know how I can install them on my boards. It has some writing on it but that is the only clue on how they are aligned. For those who need to know it is an LT1933 or LM2734Y (depending on the version.) I'm actually starting to wonder how feasible it will be to assemble these boards of mine with such tiny components, even using a reflow method.


There are two ways to identify pin 1 on a SOT23-6. One is a dot next to pin 1 on the top of the package. Most often it's not printed with the marking, but molded as a small pit in the plastic of the package, often no more than 2/10s of a millimeter in depth. A second method is a chamfer over the length of the package on the side of pin 1. From the drawing in the datasheet both the LT1933 and the LM2734Y should have the pit/dot.

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FAEs often have warned me never to refer to the marking printed to determine which is pin 1.

  • \$\begingroup\$ +1 for the chamfer. That's the method that I've seen most often. Should we put up a diagram? \$\endgroup\$ – Kevin Vermeer Jan 17 '11 at 13:26
  • \$\begingroup\$ I've heard that you should avoid using the screen-printed numbers to orient the part, but the laser-etched pin 1 ID dot is dependable. Is that what you meant? \$\endgroup\$ – Kevin Vermeer Sep 27 '11 at 10:42
  • \$\begingroup\$ @Kevin - Yes, that's what I meant, but a screen-printed dot should be reliable too, of course. I think the FAE meant that the dot doesn't have to be in the bottom left corner, but that it also could be top right, relative to the text. \$\endgroup\$ – stevenvh Sep 27 '11 at 10:53

Sometimes they have a line along one edge.


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