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January 26, 1998

Hitachi Releases the Industry's First 128M Bit EDO and Synchronous DRAM Products

- Achieved using two 64M bit DRAM chips stacked in a standard 400-mil TSOP package -

These products each use two Hitachi 64M bit DRAM chips (either EDO or synchronous) molded together in a standard package using Hitachi's stacking technology. The EDO product uses the same package as earlier 64M bit DRAMs, and the SDRAM product uses the same package (a 400-mil 54-pin TSOP II package) will be used for 128M bit SDRAMs and 256M bit SDRAMs.

The trends towards further miniaturization and increased memory capacities in PCs are accelerating. For example, while most notebook PCs currently have 32M bytes of main memory, it is expected that 64M bytes will become standard by the middle of 1998. At the same time, there are strong demands for further miniaturization in these products to provide improved portability, and thus it is simply not possible to provide more space for memory chips in such systems. In particular, while four 64M bit DRAMs are now used to provide 32M bytes of onboard memory, it would be difficult to expand this to 64M bytes. Hitachi developed the 128M bit DRAM to allow larger memory capacities to be achieved in such limited spaces.

In the EDO products, the HM5113805TD series provides an x 8-bit structure by stacking two x 4-bit 64M byte EDO DRAM chips within the package and molding them together into a single unit. Similarly, the HM5113165TD series provides a x16-bit structure by stacking two x 8-bit 64M byte EDO DRAM chips within the package and molding them together. In the same way, in the SDRAM products, the HM 5212805TD series and HM5212165TD series are formed using two 64M bit synchronous DRAM chips; using two x4-bit chips to form an x8-bit structure and two x8-bit chips to form a x16-bit structure, respectively.

Since these stacked products all use the same 400-mil TSOP-II package as 64M bit products, they can easily replace 64M bit products. Thus these products can double memory capacities without increasing the mounting space required. 8k refresh versions of the EDO products are available. It is planned to expand the product line up.

Application Product Examples

• Onboard memory for notebook personal computers
• Main and expansion memory in personal computers and engineering workstations

Pricing in Japan

• 128M bit DRAM (EDO)

• 128M bit SDRAM

Supplementary Documentation

1) EDO DRAM

• x8 bit structure

• x 16-bit

2) SDRAM

• x8 bit structure

• x16 bit structure

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