MRAM chip connection manages high speed data storage

Scientists have managed to significantly speed up the data transfer of Magnetic Random Access Memories (MRAM), meaning that the spintronics based memory could soon rival DRAM and SRAM.

While MRAM has been around for a while now it has so far been unable to reach the high speeds of its volatile memory competitors meaning that, though it offers many advantages, it has not been a reasonable alternative to more traditional RAM.

MRAM is, unlike DRAM and SRAM, able to store information after its power supply has been interrupted – as it stores information through the magnetic arrangement of storage cells rather than through electrical charge.

“As MRAM are non-volatile memory devices and if they turn out to be more widespread, the times of lengthy booting of a PC, sometimes even of mobile phones will lie in the past,” Dr Bernhard Smandek of Physikalisch-Technische Bundesanstalt research institute told TechEye.

While faster access is indeed possible with MRAM, so far it has lagged behind its competitors.

However scientists at PTB have developed a new chip connection that, in association with dynamic triggering of the component, is able to significantly reduce response times as well as power consumption and thermal load.

“Presently, only DRAM offers the possibility of fast data access. However the data has to be refreshed and is lost upon power down. Non-volatile storage is done using Flash memories,” said Dr Smandek.

“However here write speeds are severely limited. Fast MRAM might thus be used to create storage cards with high data write rates to replace Flash or for computer cache memory that does not have to be refreshed.pi

“This would enable fast mobile applications with low power consumption as read/write operation needs only address the single bit under operation, whereas in traditional RAM all bits in a row or column of the chip must be addressed.”

According to the researchers, the response rate for MRAM has been lowered from two nanoseconds, which has previously been recorded, to 500 picoseconds, corresponding to a data rate of up to 2GB/s, as opposed to the 400MB/s that has so far been developed.

The reason that no one has been able to move past two nanoseconds until now is that this is the fastest that is allowed by the physical properties of magnetic storage cells, due to the time taken to program a single cell.

When a cell has been ‘excited’ in this way in the past it has also had an effect on surrounding cells, meaning that nothing else can be programmed for the duration of these two nanoseconds, which has meant that the clock speed has been limited to 400MHz.

However the PTB scientists have been able to integrate what they call ballistic bit triggering, where the magnetic pulse used in the programming is able to target cells much more specifically, meaning that surrounding cells are not ‘excited’.

According to Dr Smandek this will allow clock rates to be achieved with MRAM “which can compete with those of the fastest volatile storage components,” and will eventually be used as computer cache memory.

While Dr Smandek says that the product is in R&D stage, a US patent has already been granted, with a European patent expected early this year.