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By Jack Ganssle

No Second Sources

Published 12/11/2006

The very first board I designed that used FPGAs, back in the early 90s, had a huge hunk of firmware. We popped out a prototype board pretty quickly, which gave the software people a test platform. The code was complex; development dragged on for over a year before the system was customer-ready.

By then we couldn't buy FPGAs. The vendor had obsoleted them in favor of a newer, bigger, faster, more feature-rich part.

Disgusted, we delayed shipping for three months while re-engineering the board with new parts from a different vendor. Those extra months of engineering and lost revenue trashed the year's profit and loss statement.

Ironically, the main impetus for designing that product was that its older version used a peculiar kind of memory device that had itself gone out of production. That vendor had notified us well in advance so we could order a sufficient quantity to tide us over for a time.

In the distant past engineers expected parts to have second sources, alternative vendors who would continue to produce their products even if the prime got out of the business. Identical microprocessors were available from many companies. Logic devices were all elements of accepted families of products. Everyone made CMOS logic. Everyone made TTL components.

Today that's much less the case. Vendors tout their own "solutions" which, while generally wonderful bits of technology are hopelessly proprietary. The customer succeeds at the whim of the vendor; if they discontinue a part, you're plain outa luck with no attractive options.

In my travels around the industry I often hear such tales of woe. So many products use components with such short lifecycles that there's a re-engineering required before the first units even make it out the door.

It's easy to understand where the problems come from. In the olden days there weren't nearly so many variants of ICs and other components. How many distinct CPUs existed in, say, 1980? Consider the 8051 or PIC today: Each of these comes in hundreds of flavors, each tuned to a narrow market segment. Second sourcing isn't financially viable.

Yet customers do need stable sources of supply. Some embedded systems stay in production for achingly long periods of time. So a few companies fill their inventories with decades' worth of parts, to the shrill howls from accounting and senior management. Though the parts may be critical to long-term success, IRS rules require depreciating them. Inventory's value - and thus the company's, since inventory is on the balance sheet - declines. That's no way to satisfy the stockholder.

The obsolescence of parts could be considered a job security program for EEs, but none of us care to work on old equipment, and it's certainly not a money-maker for the company.

What's your take? Have you had problems with parts going off the market? What action do you take?