New Serial Presence Detect (SPD) EEPROM from STMicroelectronics Fully Supports JEDEC DDR2 Standard

STMicroelectronics M34E02

Dedicated SPD chip for next-generation PC DRAM modules is available in an Ultra-Thin small package, and provides temporary lock/unlock feature

M34E02  (Click for Larger Image) May 27, 2004 - STMicroelectronics has introduced a new application specific EEPROM designed to fulfill the Serial Presence Detect (SPD) function used in the new generation of higher speed memory modules conforming to the JEDEC DDR2 specification. The M34E02 is offered in two packages, including a space-saving 3mm x 2mm Pb-free Ultra-Thin flat pack.

The SPD is used on the latest versions of the DIMMs (Dual Inline Memory Modules) that provide most of the system memory in desktop PCs and printers, and in set-top boxes. A set of parameters defined by the DDR2 (Double Data Rate Two) standard is stored and locked in the lowest 128 bytes of the Serial Presence Detect EEPROM; these parameters record information such as the module's access speed, memory size, configuration and manufacturer, and are accessed by the PC's CPU through an I2C serial interface.

The JEDEC DDR2 Standard defines minimum requirements for DIMMs from 256MBytes to 4GBytes of DRAM, and provides for faster, more reliable and more efficient performance, with a lower operating voltage, than the earlier DDR specification used in most PCs today. 400MHz and 533MHz DIMMs will be launched in volume in 2004, and DDR2 is expected to become the dominant memory technology by 2006. The use of Serial Presence Detect memories is mandatory for all new 168-pin and 200-pin DDR2 modules.

The M34E02 has a 2 Kbit (256 bytes) total capacity. It follows ST's existing M34C02 SPD, but as well as the Permanent Software Protection for the lower 128 bytes - which are write protected in response to a specific instruction sequence - a temporary lock/unlock command has been added for the convenience of DRAM module makers. This feature, and all other aspects of the device, complies fully with the JEDEC standard. The upper half of the memory remains free for scratchpad use.

The SPD operates within a single supply voltage range of 1.7V to 3.6V, as required by DDR2, and is specified for the 0 to +70 degrees C temperature range. It provides both random and sequential READ modes, and allows BYTE WRITE and PAGE WRITE (up to 16 bytes). Built using a very high quality CMOS process, the M34E02 offers minimum data retention of 40 years and has a guaranteed read/write endurance of more than one million cycles, ensuring that DIMM parameters are retained over the lifetime of the module.

The M34E02 is available in an 8-lead UFDFPN8 (Ultra-thin Fine-pitch Dual-Flat-Package) package, also called MLP8, which has a body width of 2mm, a length of 3mm, and a thickness of 0.6mm; it is also offered in a TSS0P8 package. Both use ST's ECOPACK Pb-free technology for RoHS-compliance (the EU's Restriction on Use of Hazardous Substances Directive).

Samples of the M34E02 are available now and volume production is planned for June 2004. US pricing is $US 0.19 in quantities of 10K units.

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