Could you show what's the difference of old 883C and 883D? I searched MIL-STD-883C and 883E and 883F, they all said the rise time of current waveform is less than 10 nanoseconds. I can't find the difference of them.
Absolutely. On a similar note, at one company I found out that the previous year's biggest issue wasn't fixed in the new model year. Why? Because Sales was able to hit quota anyway! This was actually a massive effort by Sales to use personal relationships, incentives, discounts, freebies--anything they could pull out of their bag of tricks to get customers to accept the previous year model with the issue. So the overseas group, noting that "sales wasn't impacted", didn't fix it. Just goes to show, things can work quite smoothly until humans get involved.
Hardware design guys are not without fault. I have a current design that I need to build that due to "a small error", when the substrate was layed out, has resulted in multiple capacitor insertions acting as leap frogging pads for bonding wires and in one part running a wire bond over top of the IC to the correct trace.
At another employer, several years ago, Same type of situation resulted in power jumping over ground on one of the devices. Things like that just don't make for a robust design and when pointed out, sales, and the design guy both responded with we'll fix it on the next rev. work around it for now.
Good question. The old 883C spec required testing with a fairly slow rise time. Actual air discharge ESD events have very fast rise times.
With the ESD protection structure on the wrong side of the input strucvture, a slow event could still safely discharge through the ESD structure. A really fast event (fast rise time) required a large current flow to discharge its energy in a short time.
The poor input gate was stuck between the bonding pad and the ESD structure. So the gate saw high voltage on the trace (between the pad and the ESD structure). That was enough to rupture the gate dielectric.
Not long after we learned all of this, MIL-STD-883C was replaced with -883D, which had a much faster rise time.