By John Keller
SAN JOSE, Calif. - Although U.S. Defense Department leaders are urging electronic systems designers to use commercial off-the-shelf (COTS) components wherever possible, semiconductor manufacturers insist that is not always such a good idea.
"We don`t accept liability for damage due to the abuse of these parts," says John Hartman, military/aerospace business development manager at Analog Devices Inc. of Wilmington, Mass. "The mil/aero houses are serving notice to OEMs that if they use our parts to exceed their specs, we notify them they do so at their own risk and that all warranties are null and void."
As pressure builds to increase the COTS content of electronic components and subsystems, integrators are increasingly likely to design parts into operating environments that exceed the parts` design parameters, say some semiconductor industry officials.
Former Defense Secretary William Perry issued a directive in 1994 for military suppliers to use COTS unless only custom-designed parts will suffice.
Sometimes system integrators diligently test components to assure they will function reliably in each application and assume liability for the upscreened chips themselves. Other times, however, integrators slip "soft" parts into harsh-environment systems and hope for the best.
Semiconductor makers are putting integrators on notice that they are not responsible if things go wrong - particularly in mission- and life-critical military and aerospace systems.
"If the airplane falls on the playground and there is a multimillion-dollar suit, the liability follows the trail of the suppliers all the way down to the component level," Hartman explains. "If OEMs choose to use COTS parts in applications for which they are not designed, the responsibility lands squarely on them. Responsible OEMs already take that position."
Leaders of National Semiconductor Corp. of Sunnyvale, Calif., sent a letter to their customers in July warning that exceeding chip design specs can lead to system failure.
"National Semiconductor has become aware some customers may be `upscreening` or `retesting` semiconductor components," reads the letter signed by Rick Cassidy, vice president and general manager of National`s military aerospace division.
"Upscreening components can be potentially dangerous to the end user," Cassidy wrote. "National products are designed to be used only within the electrical and environmental limits published in their respective data sheets. National does not authorize the use of any of its products beyond the published data sheet limits. Electrical and/or environmental testing of parts after shipment from National may cause damage or result in latent reliability problems. Such electrical and/or environmental testing or use of National products outside the published data sheet limits voids all National warranties."
"Under the Perry directive and the rush to get COTS parts are instances where OEMs went and got zero-to-seventy-degree parts and used them in extended temperature environments," says Joe Chapman, government relations manager for the Texas Instruments Military Semiconductor division, in Midland, Texas. "We cannot be liable for the misuse of a part."
Chapman explains that semiconductor manufacturers often have limited recourse against integrators who violate spec sheets. "If we know a company trying to do that with one of our lesser-grade parts, we will not sell the part to the company," he says. "But they can go to a distribution channel and buy the part and we will not know about it."
