Officially, Intel's Broadwell processor could only address RAM modules up to 8 GB thus far. This was also because of the fact that bigger SODIMMs were not available at the time. The small RAM manufacturer Intelligent Memory is the first to launch 16 GB modules which are compatible with current notebooks.
http://www.notebookcheck.net/Intelligent-Memory-16-GB-RAM-modules-for-Broadwell-notebooks.137492.0.html
I bought the same memory stick by Intelligent Memory, 1x16gb single module stick, on my Dell Inspiron 13 7348 (2015) - processor is Broadwell i7-5500U. Unfortunately, with this, it refused to boot, so I had to return.