Instrumentation • Electronics
protect the host system from malicious files and provides a new potential revenue stream when an OEM becomes the exclusive source of new and replacement keys or tokens. Truly rugged portable memory can withstand extreme
temperatures, rough use, sterilisation, chemical exposure, static electricity, dust, dirt, moisture, shock and vibration. To meet these harsh environment requirements, some manufacturers use a solid over-moulding process that encases electronic components in specially engineered composite plastic materials.
availability and are available from multiple manufacturers. This longevity significantly reduces the likelihood that OEMs will have to re-qualify new memory devices when the old one becomes obsolete. While OEM memory systems typically do a better job of
meeting the unique requirements of OEM applications, there are some design considerations that should be weighed against the benefits offered by consumer memory devices. For instance, is OEM memory affected by the consumer
memory market? Unlike low-capacity OEM memory, high- capacity OEM memory typically utilises NAN D flash technology. As a result, the long-term availability of high-capacity devices is reliant on the consumer market. However, OEM memory systems based on NAN D flash technology typically offer better long-term availability than consumer products by using qualified and consistent sources, featuring configuration control and providing built-to-last designs. Many OEM memory systems
are geared towards the low- capacity applications that are more prevalent in non-consumer embedded systems. However, as previously stated, some newer OEM memory systems offer higher capacities that match those of consumer memory products. Most important to engineers is that the memory solution specified be offered in a range of memory
Fig. 2. Nexus GB has supplied data keys to Bombardier as part of a project to help monitor and manage location of trains on the track.
However, the environmental capabilities of a portable memory device do little good unless the associated receptacle is also protected. Receptacles in OEM memory systems should also carry ratings consistent with the harsh environments where they will operate. These environmental ratings may include IP ratings, such as IP65 or IP67, or military environmental ratings such as MIL-STD-810. These ratings allow OEM memory systems to operate in harsh environments where consumer memory devices would not survive.
OEM memory systems offer a higher number of mating
cycles between the memory device and its mating receptacle: ranging from 50,000 cycles to 200,000 cycles for some OEM receptacles. For example, an OEM memory receptacle rated at 50,000 insertion cycles would last a minimum of thirteen- and-a-half years if used 10 times per day. To put that into perspective, a typical USB connector (rated at 1,500 insertion cycles) that sees the same 10 insertions per day will reach its rated cycle life in just five months. Many OEM memory products have been available
unchanged for more thann 20 years. Lower capacity devices that use EEPROM or NOR flash non-volatile memory technology have a proven track record of long-term
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capacities that best meet the specific memory requirements of the system. Deciding between consumer and OEM is the likely first
step in choosing a portable memory solution for an embedded design. In many cases, both will work. However, for successful OEM designs, engineers need to look beyond ‘will it work?’ and consider the long-term implications and the environment in which they will function. While consumer-focused components are less prevalent
in non-consumer OEM designs, it is hard to argue with the convenience, high memory capacity, small size and low cost that USB flash drives, SD cards and other consumer devices can provide. Nonetheless, the short life of consumer memory products is inescapably tied to the fast-paced consumer electronics market. Manufacturers of consumer memory products are not
anti-OEM; they are just meeting the demands of a consumer market that simply does not care about or have a need for performance requirements that are unique to non-consumer, OEM applications. When rugged construction, a high mating cycle life, secure form factors and long-term availability are higher priorities, a purpose-built OEM memory system is likely a better fit. ●
Victoria James is with Nexus GB, Midhurst, West Sussex, UK.
www.nexusgb.co.uk
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