NEC Corporation, a Japanese IT company, teamming up with Tohoku University, has developed a chip around Content Addressable Memory (CAM) technology that can save data without power and retrieve stored bits as fast as everyday RAM chips.
As per official press release:
CAM is a part of spintronics logic integrated circuit technologies that utilize the negative properties of electrons together with the spin magnetic moment (*2). The new CAM utilizes the vertical magnetization of vertical domain wall elements (*3) in reaction to magnetic substances in order to enable data that's processing within the CAM to be stored on a circuit without using power. This contrasts to conventional technologies that required data to be stored within memory. As a result, data can be saved on circuits even when power is cut from the CAM.
"Use of the new CAM in combination with existing nonvolatile memory is related to greater non-volatility of CPU for electronics and other storage devices. Furthermore, use of this new CAM enables the development of electronics that start instantly and consume zero electricity while in standby mode."
Key features of these newly developed technologies are as follows:
- High-speed data retrieval
In order for CAM to be both nonvolatile and maintain a high speed, two spintronics devices, spinning in opposite directions to one another, were connected within the same cell. In terms of constructing the circuit, writing is done once by connecting two devices in a series using recently developed three pin particles that separate the current path into writing and reading.
This new process enables cells to become more compact since the number of writing switches per element is reduced by one. Moreover, the new CAM achieve the same level of high-speed data retrieval as current CMOS based CAM that feature 5ns and low power consumption of 9.4mW.
- Approximately half the circuit area in comparison to existing technologies
In addition to the vertical domain wall element can connect in series by separating the route of current into reading and writing, the newly developed CAM circuit technologies can reduce the number of transistors from eight to three in every two cells by sharing transistors. This results in a 50% CAM area reduction.
We're talking on average a five nanosecond data retrieval times for CAM chips, which's in the neighborhood of RAM chips. Nanosecond is one billionth of a second. For comparison, solid-state drives typically have access times measured in microseconds (one millionth of a second). The step-up from millisecond-SSDs to nanosecond-CAMs roughly equals to the performance jump experienced when replacing your hard drive with an SSD (access time of hard drives is measured in milliseconds, which is a thousandth of a second). What's best, CAM chips consumer far less power than the traditional SSDs we use today because CAMs only require electricity when saving data, typically just 9.4mW of power.
For comparison, hard drives require two watts of power and SSDs less than a watt. CAMs are also simpler to manufacture than RAM chips due to only three transistors per two cells versus eight for RAM modules.