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By John McHale
SCOTTSDALE, Ariz. — Members of the VME International Trade Association, a printed circuit board industry trade advocate in Scottsdale, Ariz., are formulating a standard for measuring product reliability.
The proposed VITA guidelines, which would concern systems designs in the military and telecommunications fields, are to be an easier-to-use alternative to MIL-HDBK 217 and its descendents.
The proposed standard is called PIRMA — short for Product Integrity Requirements for Mission-critical Applications. VITA members first introduced it earlier this year at VITA's Bus and Board Conference in San Diego, says Jim Botte, technical advisor at Nortel Networks in Ottawa, Ontario.
"We are attempting to evaluate military and telecommunications and later automotive and medical technology for reliability," Botte explains. There are common electronics in all the industries, he adds.
The effort behind PIRMA is to come up with a standard that is easy to implement, says Glenn Benninger, senior engineer at the Commercial Technology Support Branch of the Naval Surface Warfare Center division in Crane, Ind. The goal is to make it free and open, he adds.
Many board designers are frustrated with MIL-HDBK-217 because they claim it does not adequately account for plastic parts and custom application-specific integrated circuits, better known as ASICs.
Some designers insist that by using MIL-HDBK-217 guidelines they often find great disparities in mean time between failure among board products that have essentially the same parts.
"It's pretty simple — everybody does their own thing," Benninger says. "A standard is needed to level out the playing field."
The VITA standard would categorize various levels of reliability areas such as temperature ranges, shock, and vibration, Botte says. The VITA members will also become more familiar with the reliability levels as they move forward, thus making it easier for them to comply when a formal standard is adopted, Botte explains.
Military designers can then list their requirements as PIRMA temperature level 3 or PIRMA shock level 4, he says.
Board vendors need an improvement to MIL-HDBK-217, says Ray Alderman, executive director of VITA. With PIRMA areas such as temperature ranges can be listed in levels A, B, C, or D, creating a much simpler, user-friendly standard, he adds.
It is too early in the process to estimate when or if PIRMA might be officially adopted, he says. "It is an enormous undertaking to create a straightforward, but not trivial robust standard for product reliability and could take some time," Botte explains.
"Many variables have to be analyzed before you can determine what is a reliable product," Benninger adds.
For more information on PIRMA contact Jim Botte by phone at 613-765-5781 or Ray Alderman at 480-951-8866.
Military & Aerospace Electronics August, 2000
Author(s) :
John McHale
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