SFF-SIG standards update: Rugged RAM and tinier CPU boards emerge in 2013
March 01, 2013
The SFF-SIG is driving specs at the small end of the embedded spectrum that CoreExpress COMs, Pico-ITX SBCs, and XR-DIMM rugged memory.
New product momentum continues to build for standards that the Small Form Factor Special Interest Group (SFF-SIG) announced during the past several years. The standards themselves address the need for smaller and more rugged building blocks. The process starts with the formation of a working group to study a certain market area and then develop or adopt a specification. Next the specification is voted upon, released, announced, and then promoted. Finally, both member companies and nonmember companies develop products that comply with the standards. Meanwhile, the hottest trends for SFF-SIG working groups right now include specifications such as tiny SBCs, rugged memory, and Computers-on-Module (COMs).
Single Board Computers (SBCs)
In the SBC arena, we’ve seen continued interest in the market for Pico-ITX in a variety of applications from medical to smart energy. The tiny 72 x 100 mm form factor is inherently rugged, as fiberglass doesn’t bend as much under shock and vibration loads as larger SBCs having the same board thickness. SFF-SIG jumped out ahead of requests for an expansion bus and defined SUMIT to anticipate the need. At that time, working group member VIA Technologies designed the first expandable Pico-ITX board using VIA’s highly integrated silicon. By now, Intel Atom-based and even Freescale ARM-based boards are on the market without any standardized bus expansion. To further develop the market for mezzanine expansion for tiny SBCs (for example, Pico-ITXe), ACCES I/O and WinSystems have introduced tiny 60 x 72 mm Pico-I/O modules. With digital I/O (GPIOs), analog I/O, and high-current FET switches, these Pico-I/O cards will help Pico-ITX SBCs penetrate automation and medical applications.
Just like with a chain, an SBC is only as strong as its weakest link. We’ve seen SBCs touted as “rugged” but yet are designed only with consumer SODIMM sockets for RAM. Consumer RAM modules don’t have mounting holes, exposing the thin gold plating on the contacts to micro-etching (rubbing) in the presence of shock or vibration. Traditionally, defense and aerospace prime contractors have had to apply epoxy to hold SODIMMs in place, but increasingly this solution is frowned upon. So the Rugged RAM Working Group met and settled on a small 38 x 67.5 mm module size with two mounting holes and true board-to-board mated connectors from Samtec with pins that form gas-tight connections. The XR-DIMM solution was shock-tested according to VITA 47 methodologies. The latest manufacturer to come online, driven by customer requests, is SMART Modular Technologies (Figure 1) with their 4 GB DDR3 two-rank design with ECC support. Not only is XR-DIMM useful for industrial, transportation, and mil/aero applications, but interest is starting to grow in communications and control applications as well because of size and reliability considerations.
Many embedded applications require very customized I/O in compact packages. To reduce the height and cost of SBCs plus stacks of I/O cards in I/O-intensive applications, Computer-on-Module architectures were invented. SFF-SIG adopted LiPPERT’s CoreExpress form factor several years ago, and now in 2013 Swiss manufacturer SysLogic has just released its CoreExpress module. The all-digital 58 x 65 mm form factor is less susceptible to analog/digital interference, focuses on ultra-low-power processors, and uses board-to-board mated connectors rather than DIMM-PC-type processor modules for ultra-rugged reliability.
The initial wave of SFF-SIG specification development has been followed by a product launch stage where the market adoption will be assessed. The group is always interested in feedback from the market and new ideas. The group is structured so that new specifications will not be hindered because of any member’s competitive self-interest; the group also has a long-term orientation, since new technologies take time to get well-established in the embedded systems market.
For more information, please visit www.sff-sig.org.