Copyright of reference designs?
Your main confusion seems to be between copying a schematic and a design.  Only the schematic is and can be copyrighted.  It's only the drawing itself that is copyrighted.  You can't, for example, copy the schematic of the reference design into a book of schematics and sell the book.

However, there is no restriction in the document of the idea behind the drawing.  Ideas can't be copyrighted.  They can be patented, but that's different from the copyright you asked about.  Since the intent of TI in providing a reference design is for their customers to use it, it would be very strange if TI patented the design and then prevent you from using it.  They want you to use their IC in a circuit, and many circuits will have significant similarities with the reference design.

Put another way, TI is giving their idea of how to use this chip freely, but not that specific drawing describing the idea.  You are free to create your own drawings that describe the same or similar ideas.