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| Post the worst datasheet lies you've caught |
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| JPortici:
--- Quote from: joeqsmith on January 02, 2024, 05:27:07 pm ---From my experience, the story normally goes something like, I find a problem. Contact company. Company states I am an idiot and they can't replicate. I provide bad parts. Company eventually puts me in touch with higher level support who states they can't replicate. In the case of Analog Devices, I get a call one day from the designer of the part. Also get a call from their factory who provides me with details on how to screen for the problem. They correct the IC in the next product line and they also add changes to their factory testing of the ICs. It's always the same, time wasted dealing with the apps engineers, sales..... and finding the people who actually know what is going on. In the case of previous part, I had found more than one problem. Once I worked the channels the first time, finding other root problems went smoother. They knew who I was and I had a bit more clout. Life of a designer. --- End quote --- can't say i can blame them for this approach :) In the firmware world, do you know how many "compiler bugs" which are actually "lack of understanding in how to write even simple statements" support receives? I have reported actual compiler bugs a number of times and the process is always the same: get the useless wall of text from first level support, have them suggest i don't knwo what i'm talking about when i reply that they sent me is completely unrelated, please reread the request and let me try with simpler words if you still don't understand, then second level asks a couple of more info that were already in the first text, then i get messaged from a member of the compiler team that is able to reproduce the problem with all the data that was there in the first post usually the middle step is skipped if i previously opened a thread in the company's forum at least i don't get sales droids to insult me asking how many units of X i plan to buy anymore, it is I who should be given a reel of parts instead whenever i find problems (sometimes really nasty ones) that they didn't manage to catch ::) |
| vk6zgo:
--- Quote from: joeqsmith on January 02, 2024, 05:27:07 pm --- --- Quote from: berke on January 02, 2024, 04:31:10 pm --- --- Quote from: joeqsmith on January 02, 2024, 04:01:02 pm ---Over the years, I've encountered several problems with brand new ICs where the companies have altered their datasheets as a result. In one case, company removed the IC from the market. One IC I used, I think the company revised the datasheet three times before I was done. If someone unfamiliar with the part used it today, they would have no idea that several modes that the hardware supports because they are no longer documented. --- End quote --- Were those modes terminally useless? Maybe someone could have used them for something? --- End quote --- In that particular case, I am using these undocumented modes for products we have in current production. The problem from the IC manufacture's perspective is they would have had to provide details about the cases I uncovered in their datasheet. While I would have thought errata sheets, I am guessing they just took the easy route and stripped the features all together. Maybe I shook their confidence. From my experience, the story normally goes something like, I find a problem. Contact company. Company states I am an idiot and they can't replicate. I provide bad parts. Company eventually puts me in touch with higher level support who states they can't replicate. In the case of Analog Devices, I get a call one day from the designer of the part. Also get a call from their factory who provides me with details on how to screen for the problem. They correct the IC in the next product line and they also add changes to their factory testing of the ICs. It's always the same, time wasted dealing with the apps engineers, sales..... and finding the people who actually know what is going on. In the case of previous part, I had found more than one problem. Once I worked the channels the first time, finding other root problems went smoother. They knew who I was and I had a bit more clout. Life of a designer. Anymore, I don't do much with new parts so I dare say most of what I run into it the company take over, marketing/sales messing up the new datasheets. --- End quote --- I've moaned on this forum before about the 4000 series monostables we used at my old work in (luckily) just a couple of transmitter site remote controls, built "in house". It's too long ago to remember the exact type number, but we used the devices to provide a quite long time delay, which was well within the range quoted in the data sheet. We had to perform a modification which required messing with the wire wrap connections to the socket holding the device, so I carefully removed the IC & promptly lost it into the "black hole" which seems to surround workbenches. No problem, plenty in the store! Big problem!---- the time delay function didn't work properly with the new one! Stealing a device from another part of the equipment, all was well, so the next trick was to check every device of that type number in the store, it was found that none of them worked in that circuit. Digging through a ton of datasheets, we eventually found, on a loose, daggy looking errata sheet that some people had been having trouble achieving short delays with the devices, so the manufacturers modified the device to work well at such delays, buggering up its performance for long delays. To "add insult to injury" they retained the original part number for the modified version & relabeled the original version with a new type number. We just bought a bunch of the relabeled ones, changed our records/schematics & were "good to go" as we only had two of those remote control units in service, but imagine if someone had thousands of them in production or "out in the field! |
| srb1954:
Category A I was using a 30ns multiplier-accumulator chip in a system running at a 32ns cycle. However, this chip occasionally spat out incorrect calculations for some multiplicand values. After a lot of time, may be 40-50 hours, investigating and attempting to replicate the worst case condition I eventually determined that the chip was not meeting its specified speed rating and was only capable of returning correct calculations in every case when operated at a 38ns cycle time or slower. Reported this to the chip distributor who admitted that their factory had known for some time that their test system set-up was not catching some marginal chips off the production line. They refunded our money for the bad chips but we were still out of pocket for the engineering time lost investigating their bad chips. |
| David Hess:
This one falls under category A. Long ago Texas Instruments released a new integrating analog-to-digital converter, and one of its advertised features, which was suppose to be a great improvement over earlier models, was a true single count zero instead of positive and negative zero, which would require external logic to fix. So we designed and built new boards with this improved converter and ... it still reported positive and negative zero. We contacted Texas Instruments and confirmed our results, but as far as I know, they never changed the datasheets and never advertised the problem. |
| joeqsmith:
--- Quote from: vk6zgo on January 02, 2024, 11:38:30 pm ---I've moaned on this forum before about the 4000 series monostables we used at my old work in ... It's too long ago to remember the exact type number, but we used the devices to provide a quite long time delay,... --- End quote --- Funny, we also used some of these old 4000 series CMOS parts for timers as well in the minute range. buffered, unbuffered, brand, all made a difference for leakage. We were pretty limited what we could use. Seems like we found Motorola UBCP worked well. We didn't want to pay extra for the higher temp parts and qualified with the cheapest. Most parameters we didn't care about. The caps were also a problem. Cheap, crap design but worked alright. |
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