JEDEC JESD8-17

This material is intended to be reflected in supplier specifications for point to point DDR devices ranging from 400 Mb/s to 800 Mb/s operation. It is a method to specify driver impedance with something other than a number that does not nec-essarily define how it operates in a real net This standard addresses this issue using net lengths and specifies how much uncertainty can exist in the data for each speed supported.