Defense Department procurement weenies insist that all military electronics be built with MilSpec semiconductors. Which cost ten times as much as commercial semiconductors. Are MilSpec semiconductors better than commercial semiconductors? No.
Many years ago I was on the design team for the anti ballistic missile radar at Raytheon. We were doing a big phased array radar for Mech Island in the Pacific. The contract called for a "brassboard" radar to be built and tested at the factory, and a second "deliverable" radar to go to Mech Island. To save money we built the "brassboard" using commercial semiconductors. We got the brass board working, and past the government acceptance tests. Then we started construction of the deliverable. Same circuit boards, same technicians, in the same shops, to the same drawings but all the semiconductors were MilSpec instead of commercial.
The deliverable didn't work. Argh. Trouble shooting revealed that the MilSpec semiconductors had lower gain, higher leakage, and could not withstand as much voltage as the commercial devices. It was so bad that we had to redesign some of the circuits to make them perform when built with lower quality MilSpec transistors.
Not only were the MilSpec devices lower performance, they had a lot of duds. I can remember going thru a brand new box of JAN2N5109TX transistors with a Simpson 260 meter and finding one in ten devices didn't work at all. That's 10 percent duds. For this we paid ten times the price of good commercial parts.
And, turns out, a fair number of MilSpec devices are counterfeit. The scammer buys good commercial parts, wipes off the commercial marking with solvent, and repaints the devices with the JAN-TX markings. Presto, chango, we turn honest commercial devices into pricey MilSpec devices. Several cases of this made the news over the years. In the last case, the defense department admitted that the counterfeit devices were as good as MilSpec and they had no intention of recalling the equipment (some of which was in outer space in satellites) to replace the counterfeits.
We could save defense money by scrapping the whole MilSpec semiconductor "thing" (boondoggle actually). Semiconductors never wear out. If the system powers up and runs and makes it thru high and low temperature testing, the semiconductors are good and will last forever.
It ain't like it was with vacuum tubes.
3 comments:
I, too, worked for Raytheon. I was there for 20 years and worked in three different divisions including Equipment on Seyon Street in Waltham, RayServ in Woburn, and Missile Systems in Lowell and Andover.
In Missile Systems many of the Mil-Spec silicon parts were made in the Microelectronics foundry in Andover (next to the Andover Missile Systems plant). Most of those worked well. It was with the out-of-house parts we had the most problems, including the JAN2N5109TX, just as you did.
Ahh, the bad old days!
I worked at the Equipment Div in Wayland in the early '70s. The project was "Ballistic Missile Div Test Project" or BMDTP for short. The building was later sold to Polaroid. When Polaroid went under they held an auction of tools and furniture which I attended. Surprise, the guy on the front desk was a guy I remembered from 30 years before. The 2N5109 was our favorite transistor due to a miraculous (for the time) Ft of 1 GHz. The commercial 2N5109's were fine, it was the MilSpec JAN-TX version that was junk.
One thing that does not surprise me is the use of 'legacy' parts in modern systems. If a part is found to be reliable and performs well, they are reluctant to go to a 'new and improved' part just because it is new and improved. Until they have years of performance data they won't make the switch. Of course some times that puts manufacturers in a bind because just about the time the defense guys want to start using the part, the manufacturer may be EOL'ing it.
One upside to this problem: some of the few 'obsolete part' foundries are making a small fortune by buying the dies and IP from the original manufacturers and continuing production of the part the defense guys (and some commercial operations) still want and need.
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