168 pin DRAM DIMM (Unbuffered) Pinout

Personal Computer Memory Module description, 168-pin DIMM Pin out.
This was a memory module [memory stick] used with Desk-top computers
The 168-pin DIMM have 84 pins per PWB side.
The Front Side board pinout contains left side pins 1-42, and right side pins 43-84.
The Back Side board pin out has left side pins 85-126, and right side pins 127-168.
168-pin DIMM memory modules would be found in Desktop computers.

Front, Left Side Signals

Front, Right Side Signals

In order to keep this page at a reasonable size, refer here for the pin out of Rear side 168-pin DIMM pin out.
The pin out above relates to the front-side of a 168-pin DIMM, the side with the memory ICs.
These memory sticks are basically two-sided printed circuit boards, with copper fingers on each side.

Data width is 64 bits per memory stick [the front side 84 pins are not connected together with the back side 84 pins]

The approximate board size. 5.375" x 1.375"

DRAM: Dynamic Random Access Memory
SDRAM:: Synchronous DRAM (Random Access Memory), Synchronous to Positive Clock Edge.
FPM:Fast Page Mode: (asynchronous) Obsolete, faster than normal DRAM, used in 386/486 computers.
EDO: Extended Data Out: (asynchronous) A superset of FPM, just faster than FPM.
All 168 pin DIMMs use either 66MHz SDRAM, PC100 SDRAM, PC133 SDRAM, EDO or FPM memory. 168 pin DIMMs have two alignment notches as shown.
The left most notch [keyway] determines the DRAM type. If the notch is centered then the memory module is Buffered DRAM [EDO or Fast Page].
If the notch is off-set to the right then the memory module is either a un-buffered DRAM/SDRAM DIMM or a buffered SDRAM DIMM.
The center notch determines the voltage. If the notch is centered then the DIMM operates off 3.3 volts.

Additional electronic Equipment manufacturers may be found by selecting the OEM Equipment icon below,
or component manufacturers may be found by selecting the Components icon below.
Back to the main Computer Memory Modules information page. For electronic device manufacturers see one of these pages:
Memory IC manufacturers [IC memory vendors]
Memory Module manufacturers [memory stick vendors]
Memory Module Acronyms [specific to memory sticks]
IC Memory Acronyms [specific to memory ICs]

Editor note; This family of memory module was used with desk-top computers, lap-top computers would use a different style.
This particular generation of memory module was used in computers before the advent of DDR memory, and is slower than DDR.
Because the DDR style is faster, that implies that this format, or memory stick implementation is out-dated and should no longer be used.
However given the long-life of military systems, these memory module could still be in use.
Regardless of the fact that memory format being out-dated, the board pin-outs are still valid.
You could also conclude that this family is fixed in time and will not be changing, given the fact that a new family of modules has replaced it.
In other words, work on this standard of memory modules is probably no longer on-going.
Newer memory stick formats are not compatible and are designed not to plug into a 168-pin memory stick socket.

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