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???
02/11/08 22:16
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#150622 - not mostly - only and who cares
Responding to: ???'s previous message
Apparently you mostly use DC-DC converters. That's probably because you design displays for mass transit vehicles.
not mostly - only

I've tried a few of those small converters along with wall-warts but I've never seen one hold an adequate noise limit. I require less than 0.1% of Vout (5 mV at Vcc=5 volts) as noise at 10% rated load and 1.0% of rated output at 90% of rated output (50 mV at Vcc=5 volts), as tested with a static load resistor. There are, of course, other constraints.
who cares, the one and only important parameter is "performance AFTER the filter".

Erik

List of 58 messages in thread
TopicAuthorDate
problems with edge triggering and noise            01/01/70 00:00      
   5v regulator,capacitors - elko and creamic            01/01/70 00:00      
      not likely            01/01/70 00:00      
         not true!            01/01/70 00:00      
   How much noise?            01/01/70 00:00      
      using a 78L05 voltage regulator IC with 220 uF cap            01/01/70 00:00      
         be conservative ... for now ...            01/01/70 00:00      
   First things first - Begin at the beginning            01/01/70 00:00      
      yes i agree..            01/01/70 00:00      
         photo            01/01/70 00:00      
            Well done            01/01/70 00:00      
               the "backside" :)            01/01/70 00:00      
                  Use Solder Wick as Braid            01/01/70 00:00      
                     is this ok?            01/01/70 00:00      
                        i found this strange looking woven wire?            01/01/70 00:00      
                  Perf Board Types            01/01/70 00:00      
                  Pad-Per-Hole PTH            01/01/70 00:00      
                     How much ?            01/01/70 00:00      
                        This Much            01/01/70 00:00      
                           other boards            01/01/70 00:00      
                     Here\'s what I prefer.            01/01/70 00:00      
            it looks quite acceptable, with caveats ...            01/01/70 00:00      
      How much noise!            01/01/70 00:00      
   Regulator problems..            01/01/70 00:00      
      sorry wrong measurements            01/01/70 00:00      
         Actuall, you were right, in part ...            01/01/70 00:00      
            Different caps..            01/01/70 00:00      
      one more issue            01/01/70 00:00      
         7805            01/01/70 00:00      
            Swop the pins around !!            01/01/70 00:00      
            agreed            01/01/70 00:00      
               what about switching noise and ripple?            01/01/70 00:00      
                  to RE            01/01/70 00:00      
                     This is a real disappointment            01/01/70 00:00      
                        numbers            01/01/70 00:00      
                           that's not what was asked ...            01/01/70 00:00      
                              yes and no            01/01/70 00:00      
                                 I've got lots of those ...            01/01/70 00:00      
                                    not mostly - only and who cares            01/01/70 00:00      
                                       It's what's before the filter that matters!            01/01/70 00:00      
                                          enough            01/01/70 00:00      
                                             not exactly ...            01/01/70 00:00      
                                                as stated before            01/01/70 00:00      
                                                   Nonsense!            01/01/70 00:00      
                                                      you can't stop, can you            01/01/70 00:00      
                                                         I love to see Erik backpedal            01/01/70 00:00      
                                                            Better start giving a hoot            01/01/70 00:00      
                                                               as stated so often, I DO give a hoot ...            01/01/70 00:00      
                                                                  as stated so often, I DO give a hoot ...            01/01/70 00:00      
                                                                     I think you are right            01/01/70 00:00      
                                                                        I too favour looking inside black boxes            01/01/70 00:00      
                                                                           blindly?            01/01/70 00:00      
                                                                              Erik ... you\'re headed for a disappointment            01/01/70 00:00      
                                                                                 If you accept datasheet blindly I cant help            01/01/70 00:00      
                                                                                    you do not get the point, do you?            01/01/70 00:00      
                                                                     not exactly            01/01/70 00:00      
                                                                        I never made any such claim            01/01/70 00:00      
         gee ... that's a negative regulator ...            01/01/70 00:00      

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