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???
09/02/06 03:47
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 		 #123558 - Exactly
Responding to: ???'s previous message
Richard said:
If the supply voltage to the supervisor chip is so low that noise and board-level voltage drop is an issue, then the problem is probably in the input voltage, the bypass, the layout, or perhaps in that the current capacity of the regulator is too low.

Exactly! Jan, is the regulator becoming hot? If so, means if the regulator is near the thermal limit, it can behave very strange, looking like a very bad regulator not offering any load regulation performance! The same, if the input voltage is abnormally low or high! You should at least have 3V difference voltage between input and output, but no more than about 7V. Look with a scope to take into consideration the input ripple!!

Kai

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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