Memory Module Technologies: TCP, EPOC and FEMMA

It appears that both Kingston and Elpida were hard at work trying to perfect the stacking dilemma independently. The EPOC and Elpida 2GB modules are different although the basic concept is similar--that an elevated package is used to hang over a lower tier package without contact, which is better and simpler than prestacked packages. The difference is that EPOC use more cost effective TSOP packages on the top and small CSP at the bottom, whereas Elpida uses more expensive TCP on both tiers. The top TCP packages must have longer leads to avoid tangling up the leads of the lower tier TCP, thus, more space between adjacent packages is required.

Meanwhile, Kentron has proposed the smaller 1.2 inch size DIMM as a new industry standard to JEDEC, the engineering standardization body of the Electronic Industry Alliance. The standard is needed, the company said, because as the Internet grows, the need for higher memory and more servers grows along with it.

While these memory module technologies are currently targeted towards the server market, the main advantages of density, size and thermal dissipation also apply to desktop systems, and server technology always filters down to the desktop market at some point.

Kingston's EPOC technology is currently shipping for PC133, Registered, ECC, 1GB modules, with DDR coming very soon. Elpida offers their technology as a 2GB DDR SDRAM DIMM, while Kentron offers FEMMA in a variety of formats, for both SDR and DDR SDRAM and at various sizes.

Special thanks to Heather Jardim at Kingston for the EPOC Technology images.