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March 23, 1998

Hitachi Releases the Industry's First 256M-byte 168-pin Large Capacity DIMM and 128M-byte 144-pin Large Capacity SODIMM Achieved by Using 64M-bit SDRAM

- Large capacity memory modules that support 100MHz high-speed operation for desktop/notebook personal computers -

The TCP stacked modules apply a three-dimensional mounting technology that stacks two TCPs on a module substrate. Hitachi has already commercially released the 64M-byte 168-pin DIMM and 32M-byte 144-pin SODIMM for PCs and servers by using TCP of 16M-bit EDO DRAM and SDRAM. The technology introduced here enables achieves stable supply of large capacity memory modules for desktop and notebook personal computers at low cost and high-speed operation using 64M-bit SDRAM TCP. The 256M- byte module 'HB52R329E2' for desktop computers also handles a 100MHz memory bus.

Along with the recent trends towards increased performance in PCs and increased size in PC applications, the memory capacity installed in current PCs is also increasing. Meanwhile, as seen typically in notebook PCs, the space allocated for this memory is getting smaller every year, and the number of sockets to hold memory modules is limited. Therefore, even higher density memory modules are being required to support increased memory capacities without changing the size of the modules themselves. The main technique need to increase fixed size memory module capacities up to now has been to increase the capacities of the ICs mounted in those modules. However, when 64M-bit SDRAMs are used in the existing TSOP package, 64M bytes is the limit for a 144- pin SODIMM and a height of 1.15 inches is necessary.

Responding to this problem, Hitachi has developed a three- dimensional mounting technology that mounts 64M-bit SDRAM TCP packages in two layers. Using this technology, Hitachi has succeeded in the commercial production of the 128M-byte 'HB52R168DB' with 1-inch height, which has double the capacity of the existing 144-pin SODIMM. This product is a 3.3-V power-supply voltage product that achieves burst mode ^*2 cycle times of 10ns (100MHz). This product has a 16M x 64-bit memory organization and is an unbuffered type for use in PCs. It is a 144-pin SODIMM with external dimensions of 67.6 x 25.4 x 3.80 mm that conform to the JEDEC^*3 standards. As such, it can be used as a direct replacement for 32M-byte and 64M-byte SODIMMs that use TSOP 64M-bit SDRAMs. (The height of the 128-byte SODIMM is 1 inch, which is less than those of 32M-byte and 64M-byte SODIMMs whose heights are 1.15 inches.) Planed developments in this area include application of this three-dimensional mounting technology using 256M-bit SDRAM to create 1G-byte 168-pin DIMMs for high-speed/ high-performance desktop personal computers.This specification is the Un-Buffer type that is suitable for notebook PCs.

Hitachi also has commercially released 'HB52R329E2', which can handle up to 256M bytes, double the capacity of the existing 168-pin DIMM. This specification is a Registered type suitable for servers and high-end personal computers. The memory capacity can be increased to 1G bytes by using these 256M-byte modules in four sockets on the PC motherboard. Increased capacities and high-speed data transfer/ processing capabilities are required in notebook PCs to provide good response times during manipulation of video and audio information. These properties can be easily achieved by using SDRAM devices in the memory modules. It is a 168-pin DIMM with external dimensions of 133. 37 x 38.10 x 4.00mm that conform to the JEDEC standards.

Plans also call for applying this technology using 256 M-bit SDRAM to large capacity 512M-byte SODIMM for notebook personal computers. This will position the TCP stacked modules as high-speed, high- performance, high-density, and large capacity modules that support operation at 100 MHz, as standard products. Hitachi will also support custom applications for this technology.

Notes:

1. SODIMM (Small Outline DIMM):

Developed by reducing the module width and size of DIMM (which is normally 168 pins) and is mainly used for notebook personal computers whose space is limited. DIMM stands for Dual Inline Memory Module and is mainly used for workstations, servers, and desktop PCs.

2. Burst mode:

The first data access is the same as for the existing DRAM. However, for second and subsequent data accesses, input/output operations are performed at high speed synchronized with the clock cycle.

3. JEDEC (Joint Electronic Device Engineering Council):

Committee related to the U.S.A standards; prescribes the standards of IC package sizes and pin assignments.

Pricing in Japan *Provided for reference only

Product name	Capacity	Bit organization	Bank	Sample price (yen)
HB52R329E2-B6	256M bytes	32 x 72 bits	2 banks	150k
HB52R168DB-10	128M bytes	16M x 64 bits	1 bank	60k

Specification

Item	HB52R329E-B6	HB52R168DB-10
Bit organization	32M x 72	16M x 64
Bank organization	2 banks	1 bank
Mounted SDRAM specification	4M x 4 x 4 banks 36 SDRAMs	4M x 4 x 4 banks 16 SDRAMs
Register/PLL	Register/PLL	No
Capacity	256M bytes	128M bytes
Supported memory bus	PC100	PC66
Interface	3.3V LV-TTL	3.3V LV-TTL
External dimensions	168-pin DIMM 133.37mm x 38.10mm x 4.00mm	144-pin SODIMM 67.6mm x 25.4mm x 3.80mm

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