OK, but can we agree on what we disagree about? Ironically, I understand and typically would agree with your main thesis about not relying on typical specs or special parts, but I just don't think it applies to this case the way you think and since you've come here to publicly pillory some hapless EVSE designer who isn't here to defend himself, I thought I'd take up his cause.
Right? Like, you can't compare an op-amp to an FPGA... the FPGA is exponentially more complex. Obviously you're going to have problems testing an FPGA, you can't test every path under every voltage and temperature, in every single unit, under every possible combination of inputs and internal states.
The op-amp has exactly one [continuum] internal state*.
They aren't the same damn thing!
A more direct comparison would be
a single gate, or gate path or LUT/LE/block in an FPGA. Maybe a couple inverters (74HC3G04 let's say?) to be more concrete. Can you characterize the delay of one specific path? YES. Can you do it over voltage, temperature, etc.? YES. Do you want to in production? Probably not. Can you do it statistically? Probably not (e.g. sampling parts from a lot/batch, or even just sampling random LEs among the fabric -- there will be some distribution over the die itself), but it depends how much margin is required by the application. I mean, in any case, it reduces to a statistics problem, and if you're looking for a 99th percentile say, that's easily enough done by sampling; but if you need the 20th percentile lucky hotrods, good luck and have fun grinding out all that testing. But notice these latter questions are all
practical ones. Which can have different answers for different circumstances. Discarding these possibilities out of hand would be silly.
It sounds like OP is just very familiar with the high-complexity side of things, where it is practical to discount such possibilities out of hand, but forgets when they can again be reasonable to consider.
*The dominant pole; well, several if you include the higher order poles above fT but they are also largely irrelevant in practice, or beyond just the lowest few.
Mind, I don't have any complaints at all, in principle. I wholeheartedly support, understand,
and use, such principles in my own work. But apparently some would think I'm some horned devil because I allow practical exceptions to those same principles...
Or--maybe I've grossly misinterpreted or misunderstood the intent here, or the concepts at work. I haven't worked with, say, Six Sigma in a very long time (and that occasion was pretty superficial, heh). I'm sure my statistics are rusty. I may be grossly mis-understanding/representing the complexity or cost of these controls or inspection or testing procedures.
But if no one steps up to critique my points, I'm left to assume I have asserted them correctly and rightly, that most people here generally agree with them...or at least don't disagree strongly enough to complain about it. I would love for my arrogance to be knocked down a peg, as it needs to from time to time, but, y'know, I'm only going to do so much research on my own here. Someone, please, be the change you want to see! ( ??
)
Tim