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• Memory Configurations: JESD21-C JESD21-C, JEDEC Configurations for Solid State Memories, is a compilation of some 3000 pages of all memory device standards for solid state memory including DIMM, DRAM, SDRAM, MCP, PROM, and others from September 1989 to present. The document is divided into sections for ease of use.
• Originally known as the Joint Electron Device Engineering Council, JEDEC has since rebranded itself to to become the JEDEC Solid State Technology Association. The international body works with over 300 member companies to develop, implement and standardize microelectronic technologies like RAM.
• JEDEC DDR4 standard has the following 2666Mhz timing defintions: DDR4-2666T (17-17-17) DDR4-2666U (18-18-18) DDR4-2666V (19-19-19) DDR4-2666W (20-20-20) Does that mean that all sticks that have different timings from those above are out of spec even if they don't use XMP? For example, is a.

The ability to use an SDRAM memory from any manufacturer it is necessary to have a common standard. To enable SDRAM DDR memories to be sourced from any supplier, a standard has been drawn up by, JEDEC, Joint Electron Device Engineering Council.

JEDEC Standard No. 88E - i - Foreword This dictionary was originally prepared and edited by a special Working Group consisting of JEDEC consultants Fred A. Mann and Frank S. Stein, under the direction of the JEDEC Board of Directors, and is periodically updated by JEDEC Committee JC-10 on Terms, Definitions, and Symbols. After the 1st edition. JEDEC has issued widely used standards for device interfaces, such as the JEDEC memory standards for computer memory (RAM), including the DDR SDRAM standards.

In this way it is possible to equipment manufacturers to source their components from any manufacturer of DDR SDRAM knowing that they are interchangeable. This is important when it is necessary to be able to state a second source on any components.

This can only be done if they conform to the same standard. Accordingly JEDEC developed their standard JESD79 to enable manufacturers of DDR SDRAM to produce product that was interchangeable.

JEDEC DDR SDRAM Standard JESD79 outline

The JEDEC DDR SDRAM specification or standard defines all required aspects of 64Mb through 1Gb DDR SDRAMs with X4/X8/X16 data interfaces. It includes a whole variety of elements including features, functionality, ac and dc parametrics, packages and pin assignments.

The DDR SDRAM specification is expanded will be expanded to formally apply to x32 devices, and higher density devices as well.

The aim of the JEDEC JESD79 DDR SDRAM Standard is to define the minimum set of requirements for 64Mb through 1Gb, X4/X8/X16 JEDEC compliant DDR SDRAMs.

This enables system designs based on the required aspects of the specification to be supported by all DDR SDRAM vendors providing JEDEC compliant devices.

JEDEC DDR SDRAM Standard JESD79 releases

Jedec 1r

As with any stanard, the JEDEC 79 standard has undergone a number of updates and revisions to enable it to meet the current requirements, keeping pace with technology:

Jedec Mipi

JEDEC JESD79 Releases
JESD79 Release Verson	DDR Type
JESD-1 (June 2000)	DDR
JESD-2	DDR2
JESD-3	DDR3
JESD-4	DDR4
JESD-5

Jedec Timings Table

Updates of the individual JESD standars are of the form JESD-XV, where X is a numeric indicating the standard version or type, and V indicates the version of that standard, e.g. JESD-3F is version F of JESD-3 for DDR3 memories.

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