This is a unidirectional TVS diode so it's important to install it on the the correct orientation. The STEP models I find on 3rd party sites for this X1SON package have no polarity indication and, for inspection purposes, I believe from previous posts that the shaded section on the part shown on the datasheet is not the actual marking on the part. Can TI:
1) Update the datasheet or package sheet indicating what is actually printed on the part, and
2) Provide a step model with a polarity indicator, or else at least
3) Paste an drawing or photo of what the top of the part looks like and explain how to determine the pin 1 side?
Best Regards,
Ben
