DDR SSTL Interface

DIMM


I just added a new page covering SSTL switching levels, including SSTL3, SSTL2, and SSTL18.

SSTL-18 is used as the electrical interface for the DDR II memory standard, and the SSTL-2 specification is used with the DDR I memory standard.

The new SSTL page is located under the IC bus listing at:www.interfacebus.com/SSTL_Logic_Interface.html. With that new page, three additional pages were up-dated to point to that new link. The DDR 1 DIMM, and DDR2 DIMM pages and the Interface IC Buses page were updated to include the new link.

The Sub Series Termination Logic [SSTL] standards defined under JEDEC are electrical only specifications, which means normally they only define the timing and switching levels.

DDR I memory modules are currently in wide spread production, while DDR II is seeing only limited use. In fact, AMD does not even support DDR2 memory yet. AMD will not support the DDR II standard until they introduce their new M2 processor socket which is not due out until the second quarter of 2006. The M2 socket will provide a re-designed on-die memory controller allowing DDR-2 support, and at the same time obsolete the processor socket 939.

My system uses a socket 939 AMD processor. I'd like to get my next system early next year, so I my be stuck with my current socket and DDR I memory modules again. I doubt I would wait another four months just to pay a premium for the new stuff. Although the price difference between DDR and DDR2 DIMMs seems to be zero. I'm sure the M2 socket will be pricey when it first comes out. That may just leave me with a dual core 939 processor with the same DDR memory

DDR stands for Double Data Rate [Memory], DDR I may also be seen as DDR1 or just DDR, and DDR2 may also be DDR II.
DIMM stands for Dual In-Line Memory Modules

You can find definitions, speed grades and a list of manufacturers on the Memory Module page.