LP2985

Wondering if I could get some help with some info from TI regarding the LP2985 product. We are
currently using a some LP2985s, part#s LP2985AITP-5.0, LP2985AITP-3.3, package:
TPA05GAA and are experiencing some reliability issues (we think, it's early to
tell). We are having quite a bit of fallout during production at test, but
we've seen a few that failed after test, so raising some concern. The
percentage is roughly 1%, and our biggest hitter for yield defects, we've seen
between 30-50pcs that have failed, at various points during the production run
(we use 16 per board, ~100 per system).



Initially we wanted
the leaded version but that was not available during the production and looks
to be not available in the future, not sure though as it is now a TI part, was
initially a National part. I found an app note# 1112 with some comments about
reliability or lack thereof with eutectic solder, also they want different pad
sizes vs ball diameter. We are using the YPB package with 10mil pads, I wonder
if we should be using the YZR package as it prefers a larger pad size (we can't
go smaller due to copper thickness vs etching). Is there a YZR package that is
pin compatible, and could this resolve reliability issues? Also, is there a
leaded version available from the factory?



Any help would be
greatly appreciated!