first pin because it is not marked by a point
You will see that one of the edges of the plastic package is cut at 45 degrees
above the pins (bevelled or tapered) while the other edge is cut at 90 deg as
The edge which is cut at 45deg indicates the pin 1 location. You can see this
on page 23. The diagram on the right, which shows the SOIC package from the
end, shows that the left hand edge is tapered while the right hand edge is
nearly at 90deg.