A lot of ICs are just not interesting enough to make it into
a peer reviewed publication.
Many companies see no value in publishing the most useful
innovations, which are competitive advantage, and won't
let their engineers submit papers on the "good stuff".
And then there's that some companies just do a real bad job
of applications support and design collateral. But it would be
unusual to find nothing at all for a part, at its manufacturer,
if it's still current production.