Small Outline Dual Inline Memory Module

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PC6400 DDR2 SO-DIMM (200 pins)
PC3-10600 DDR3 SO-DIMM (204 pins)
SO-DIMM slot on a motherboard
Two different (a 1 GB bar (Samsung) and a 2 GB bar (Mustang)) SO-DIMM modules DDR2 PC5300, installed ready for use
Comparison of 200-pin SO-DIMMs for DDR SDRAM, DDR2 SDRAM and DDR3 SDRAM (including dimensions)

SO-DIMMs ( Small Outline Dual Inline Memory Modules ) are memory modules that are mainly used in notebook systems. Due to their design and high energy efficiency, they are particularly suitable for this purpose.

The modules (like the larger DIMM modules) have separate connections on each side of the board and are 67.6 mm wide and 30 mm high in the DDR versions. In order to avoid the installation of incompatible modules, the different versions have notches at different points in the connection strip.

Installation

Unlike DIMMs, which are inserted perpendicular to the board, SO-DIMMs are often inserted at an angle and then pressed down so that they are parallel to the board, where they snap into two springy retaining tabs on the side. In this way, very flat hardware designs are possible.

Specifications

The standards for memory modules are adopted by the JEDEC Solid State Technology Association . The different variants differ externally in the number of contacts and the notches in the contact strip. The most important variants:

  • SO-DIMMs, 072 pins, with FPM , EDO or SDRAM chips with 5 V or 3.3 V (since 1997)
  • SO-DIMMs, 144 pins, with EDO or SDRAM chips with 3.3 V (since 1999)
  • SO-DIMMs, 200 pins, with DDR or DDR2 SDRAM chips (since 2003)
  • SO-DIMMs, 204 pins, with DDR3-SDRAM chips (since 2010)
  • SO-DIMMs, 260 pins, with DDR4-SDRAM chips (since September 2014)

The RAM module specifications are defined by various JEDEC working groups and are collected in their standard document JESD21-C . Chapter 4, "Multi-Chip Memory Modules and Cards", contains the official specifications for multi-chip modules, including a. also for SO-DIMM modules:

page Number of pins designation Last rev.
4.04.04 072 DRAM SO-DIMM 06/1997
4.04.05 088 DRAM SO-DIMM 06/1997
4.05.05 144 DRAM SO-DIMM 03/1999
4.05.06 144 SDRAM SO-DIMM 03/1999
4.05.08 144 SGRAM / SDRAM SO-DIMM Family 10/2000
4.05.09 144 DDR SGRAM SO-DIMM 03/1999
4.20.03 144 PC133 SDRAM Unbuffered SO-DIMM 10/2003
4.20.06 200 PC-2700 / PC-2100 / PC-1600 Unbuffered SO-DIMM SDRAM 10/2003
4.20.11 200 DDR2 SDRAM Unbuffered SO-DIMM 06/2008
4.20.16 144 EP2-2100 DDR2 SDRAM 32b SO-DIMM 02/2007
4.20.18 204 DDR3 SDRAM Unbuffered SO-DIMM Design Specification, Rev 2.0. 12/2010
4.20.21 204 EP3-6400 / EP3-8500 / EP3-10600 / EP3-12800 DDR3 SDRAM 72b-SO-DIMM 01/2010

The table of contents and other parts of the collection can be viewed, but registration is required to download the standard documents. Individual standard documents such as B. are made available in part by chip manufacturers.

Web links

Commons : SO-DIMM  - album with pictures, videos and audio files

Individual evidence

  1. Micron Technical Note: Summary of Common DRAM Module Form Factors
  2. JEDEC: Memory Configurations: JESD21-C (accessed April 8, 2011)
  3. JEDEC: Current SO-DIMM specifications (accessed on April 8, 2011)
  4. a b micron.com - JESD21-C 4.20.6: 200 pin, PC2700 DDR SDRAM Unbuffered SO – DIMM REFERENCE DESIGN SPECIFICATION ( Memento from September 23, 2010 in the Internet Archive ) (PDF; 152 kB)