DRAM Goes Hot and Cold

TORONTO – As many big memory makers focus efforts on non-volatile options such as perfecting 3D NAND, and others work to get perennially niche memories into wider markets, DRAM has found itself in the situation of being a low-margin, commodity memory in a slowing tablet and PC market.

However, there are areas where DRAM still makes the most sense from a performance, density and cost perspective, evening as some vendors look to replace it, as Everspin has been looking to do with MRAM, for example. Virtium has focused on targeting its DRAM products in specific industry verticals, said Scott Phillips, Virtium's vice president of marketing, eschewing the consumer and enterprise markets.
Founded in 1997, the company started out primarily as a DRAM supplier. In the last four years or so, it has seen more NAND flash opportunities, particularly for SSDS in the industrial and embedded segments, which are much slower moving and need support over long life cycles, Phillips told EE Times in a telephone interview. “They create a design and they want it to last 10 years," he said.
In the case of medical applications, in can take as long as three years to qualify memory. “We're still supporting SDRAM from 12 years ago," Phillips said.
Phillips said Virtium finds itself in markets that large vendors such as Micron have exited. But the company's real niche is offering ultra-low-profile (ULP) RDIMM and Mini-RDIMM form-factors. Virtium's memory modules still conform to JEDEC standards, but offer form factors other players don't focus on, said Phillips.
Virtium recently announced new high-capacity DRAM targeted at height-restricted blade servers, 1U rack designs, single-board computers, mezzanine cards, and a range of designs with space constraints. The 32GB ULP RDIMM and Mini-RDIMM memory modules use a PC4-2400 interface and are industrial temperature rated between -40 degrees Celsius to 85 degrees Celsius, said Phillips. Virtium's ULP memory modules are 17.78mm, compared to standard low-profile modules' 18.75mm.
Phan Hoang, Virtium's vice president of research and development, said that thanks to the growth of data, video and voice over the Internet, Virtium's telecom customers continue to require higher density memory modules to support the amount of traffic through line cards. “Density has become more and more important in telecom to increase capacity," he said. “They are constantly looking at higher speeds and higher densities that line cards can handle."
Virtium is looking to meet the needs of applications with modules that can handle the heat and environments with poor airflow, such as ATMs, said Hoang. Its latest modules include the option of conformal coating. It's not only temperature that can be an issue, he said, whether extreme hot or cold, but also humidity, particularly for edge of network environments.

Virtium's ULP memory modules are 17.78mm, compared to standard low-profile modules' 18.75mm.

Hoang said that while SRAM offers some benefits for certain applications, and MRAM can offer very high speeds, the density of individual chips still can't compete with SDRAM. “There's a lot of things that the industrial space requires that it's in our wheel house," Hoang said. The company is seeing more designs in the last six months that are moving to DDR4 for speed, power, and density, and will be in service for a long time.
Phillips said Virtium has a roadmap to release even higher density DDR4 with 64GB in the same ULP RDIMM and mini-RDIMM form factors in the second half of the year.
Jim Handy, principal analyst with Objective Analysis, said all of today's and tomorrow's computers are now DDR4-based, so it makes sense that any systems Virtium wants to sell into are DDR4 systems, regardless of industry. “The dynamics that are reducing the amount of desktop computers is probably not going to hurt Virtium's market," Handy said, since industrial control PCs are usually required, rather than discretionary spending.
While DRAM lacks the persistence that MRAM has for applications such as caching, DRAM still the most cost-effective option for a wide array of applications. “DRAM is very cheap," said Handy. “All persistent memories cost more than DRAM."
Handy estimates MRAM is about 10 times the price of DRAM right now.
Although Virtium is touting its smaller form factor as a differentiator, Handy said it's not all that significant, noting the difference from a standard DIMM is less than a millimeter What's more advantageous is selling into harsh environments that require high reliability such as telecom and automotive, particularly the wide temperature range and the protective coating. “There's not an awful lot of differential in DRAM," he said. “It's very much commodity especially if you make it for commercial temperatures."

http://www.eetimes.com/document.asp?doc_id=1329645