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???
08/31/06 15:05
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 		 #123443 - No such thing as luck in any acceptable design sce
Responding to: ???'s previous message
The problem was a combination of not-so-perfect design, and bad luck.
No such thing as luck in any acceptable design scenario.

But I don't accuse the designer (who already left our company anyway). The supervisor is obviously a bit too fast
No such thing as 'supervisor too fast' only 'incorrect decoupling practices'.

I know, I know, stay on the safe side... Honestly, did this never happen to any of you?
I have posted several times about the idiot that put all decoupling caps in one corner of the board (that is where they are on the schematic, is it not?). Also I have posted about the 1" trace to the decoupling cap for a Microchip supervisor where occasional false resets were cured by soldering a cap directly across the chip.

When is the general population (including Jan's 'designer') going to understand that a trace is not a trace, it is a series of inductors with capacitors to the sorruondings.

Erik



List of 44 messages in thread
TopicAuthorDate
78x05 output voltage tolerance            01/01/70 00:00      
   5%            01/01/70 00:00      
   Selection needed...            01/01/70 00:00      
      5%, 10%, it's all there            01/01/70 00:00      
         for decades, 5% was "standard." What's changed?            01/01/70 00:00      
         What standard do you mean??            01/01/70 00:00      
            "if"            01/01/70 00:00      
               Don't you test your circuits?            01/01/70 00:00      
                  it's already a pain...            01/01/70 00:00      
                     if you do, I'll take my cap off to you :)            01/01/70 00:00      
                  Consider the specifications            01/01/70 00:00      
   is it a Microchip supervisor?            01/01/70 00:00      
      the conclusion            01/01/70 00:00      
         No such thing as luck in any acceptable design sce            01/01/70 00:00      
            everyday we learn something...            01/01/70 00:00      
         Check it with a >5.0V outputting 7805!            01/01/70 00:00      
            it will work...            01/01/70 00:00      
               oh 'testing'            01/01/70 00:00      
            Getting more than 5 v from 7805            01/01/70 00:00      
               I would use a resistor instead of a diode            01/01/70 00:00      
                  see the datasheet, it shows how to do that...            01/01/70 00:00      
                     It's noise, I guess...            01/01/70 00:00      
                        some noise            01/01/70 00:00      
               the u (micro) is only specified to 5.25 or 5.5 Vol            01/01/70 00:00      
   I just had an idea...            01/01/70 00:00      
      Don't go off chasing that rabbit!            01/01/70 00:00      
         digital design practice            01/01/70 00:00      
            Safe side...            01/01/70 00:00      
         Exactly            01/01/70 00:00      
      Getting low output...            01/01/70 00:00      
   get this in your head            01/01/70 00:00      
      Not so fast...            01/01/70 00:00      
         oh, how many designs have failed because            01/01/70 00:00      
            No, no, I have not said this            01/01/70 00:00      
            it depends on the source ...            01/01/70 00:00      
               Yes,...            01/01/70 00:00      
                  There's a critical difference ...            01/01/70 00:00      
                     Of course, there is!!            01/01/70 00:00      
                        whst do you refer to?            01/01/70 00:00      
                           This was in the '70's, before many restrictions            01/01/70 00:00      
                              caught by "legal relabeling".            01/01/70 00:00      
                                 That's not what I remember            01/01/70 00:00      
                                    continuing the story            01/01/70 00:00      
                                       The way it used to work ...            01/01/70 00:00      

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