JESD79-4 spec

This document defines the DDR4 SDRAM specification, including features, functionalities, AC and DC characteristics, packages, and ball/signal assignments. The purpose of this Standard is to define the minimum set of requirements for JEDEC compliant 2 Gb through 16 Gb for x4, x8, and x16 DDR4 SDRAM devices. This standard was created based on the DDR3 standardn (JESD79-3) and some aspects of the DDR and DDR2 standards (JESD79, JESD79-2). Each aspect of the changes for DDR4 SDRAM operation were considered and approved by committee ballot(s). The accumulation of these ballots were then incorporated to prepare this JESD79-4 specifications, replacing whole sections and incorporating the changes into Functional Description and Operation.