This document defines the DDR2 SDRAM specification, including features, functionalities, AC and DC characteristics, packages, and ball/signal assignments. The purpose of this Specification is to define the minimum set of requirements for JEDEC-compliant 256 Mb through 4 Gb for x4, x8, and x16 DDR2 SDRAM devices. This specification was created based on the DDR specification (JESD79). Each aspect of the changes for DDR2 SDRAM operation were considered and approved by committee ballot(s). The accumulation of these ballots were then incorporated to prepare this JESD79-2 specification.