原创 Phantom components

Enter an engineer I once worked with who had a serious knack for choosing seemingly phantom components that never made it to the final design. In fact, he had such an extensive track record for doing this that we called him “Mr. VVI” behind his back: for Vanished Vendor Item.

Mr. VVI gave every other engineer in the department grief for being “a dinosaur.” In his mind, the fact that we all used components that were tried and true meant that we were highly unimaginative engineers who always played it safe. As far we he was concerned, we might as well have been living in the La Brea tar pit.

We stood by, quietly gleeful as he racked up thousands of dollars in redesigns to compensate for his vanished vendor items in project after project.

There was a lot of competition in the late 1980s among AMD, IDT, Cypress, and other semiconductor companies to develop the fastest FIFO. Naturally, Mr. VVI just had to use the fastest one advertised, which, as I recall was 25 nanoseconds read time. The rest of us got by with a relatively sluggish 50 ns.

Since Mr. VVI had received actual sample devices, he decided to put sockets on his board (he would need them!). He had his circuit card populated and proceeded with testing.

Although all of the control signals seemed correct, he was not able to get any output from the FIFO. There wasn't much sympathy among the ranks, I can tell you that.

After a couple of weeks, he took the chip over to the reliability lab. They popped the cover off the chip and discovered that there was no die inside!

In the two months since he had received the samples and subsequently discovered the empty chips, the manufacturer was able to get the chips to work in functional units. So Mr. VVI got a “mulligan.”

Dwight Bues graduated from Georgia Tech with a BSEE in computer engineering. He has worked in power generation, communications, RF, command/control, and test systems for 30+ years. He is a Certified Scrum Master and teaches courses in architecture, requirements, and IVV&T.