PORTLAND, Ore. Serial magnetoresistive random-access memory (MRAM) could find wider use in the emerging smart meter market.
Everspin Technologies Inc. (Chandler, Ariz.), the spinoff of Freescale Semiconductor Inc., said its new serial peripheral interface also could make its MRAMs popular in industrial control, automotive and printer applications.
| The larger fixed area of each memory cell shows the bottom electrode attachment, while the top free layer has a cap.|
"Smart meters need to data log your usage, and MRAM is the memory technology of choice for that application, because it can continuously log data right up to the point where you get a power glitch," asserted Everspin CEO Saied Tehrani.
MRAM does not store data as a charge but rather in the magnetic polarization of a ferromagnetic plate. Two plates are separated by an insulating layer, the bottom layer pinned to a particular magnetic polarity. The other layer programmable. When the two layers match, a "0" is stored. If they have oppostie polarities, then a "1" is stored. Reading is accomplished by measuring the resistance of the memory cell.
Other memory technologies, such as flash, EEPROM and FRAM, offer nonvolatility, but Everspin claims MRAM offers a higher degree of security due to its simpler programming method, which works like fast SRAM. Other nonvolatile memory technologies, Everspin claims, require extra steps to insure that data is not lost if power is interrupted during read/write cycles.
MRAMs are already used for critical program and data storage requirements in extreme environments. Everspin recently won a contract from Airbus to supply 4- and 16-Mbit MRAMs for the flight control computer on the next-generation Airbus A350.
The new serial MRAM models will extend the nonvolatile memories reach into low-cost consumer devices and industrial controllers that leverage the simplicity of designs that do not require a parallel interface to memory.
Everspin's new serial MRAM family is available in 256 Kbit, 512 Kbit and 1 Mbit densities. A 4-Mbit version is due out next year. The company said it also plans to increase the density of its parallel MRAM devices to 16 Mbit by next year. These densities are about 1,000 times less than flash densities, but are aimed at critical applications that do not require high densities but need ultra-high reliability.
MRAM memory cells require no write delay times, run at clock speeds up to 40 MHz and are estimated to retain their values without power for up to 20 years. Everspin is currently the only supplier of commercial MRAM memory chips. However, several other companies are planning to enter the market, including Crocus Technology, Grandis, IBM-TDK, Samsung, Toshiba and Avalanche Technology.