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???
06/15/08 17:43
Modified:
  06/15/08 17:53
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 		 #155929 - yes, and no and I think the theory is flawed
Responding to: ???'s previous message
Would'nt inductor be better than resistor here? No DC losses/ drops.
a small inductance, yes, a large one, no.

In the general respect (regardless of inductor, resistor) I think the theory is flawed. If you bypass the resistor at the ground pin with a capacitor (to ground) as Richard proposes it will bypass any 'noise' the MAX generates oblitterating the resitance to pulses. This makes the resistor only have DC significance which is deterimental. If you make it a LC circuit, you may end up with aa unwanted oscillator.

Erik

List of 31 messages in thread
TopicAuthorDate
Resistance in the supply rails            01/01/70 00:00      
   inductor instead of resistor            01/01/70 00:00      
      yes, and no and I think the theory is flawed            01/01/70 00:00      
         Spice?            01/01/70 00:00      
            That would probably help, but ...            01/01/70 00:00      
      That's what I said            01/01/70 00:00      
         Not in the gnd path!            01/01/70 00:00      
            Well ... this normally doesn't work so well, but            01/01/70 00:00      
   If this scheme is used it would also be well to...            01/01/70 00:00      
      This does increase the supply impedance            01/01/70 00:00      
         please clarify with a simple schematic            01/01/70 00:00      
            the bypass cap\'s always go between Vcc and Gnd            01/01/70 00:00      
               Which Vcc, Which gnd            01/01/70 00:00      
                  There's a cap on either side of the resistor(s)            01/01/70 00:00      
                     is it            01/01/70 00:00      
                        Not quite ...            01/01/70 00:00      
                           don't use a resistor in the GND connection            01/01/70 00:00      
                              What >good reason< could this be??            01/01/70 00:00      
                                 What good reason could this be??            01/01/70 00:00      
                                    Using a resistor in the GND connection...            01/01/70 00:00      
                              How would that come to pass?            01/01/70 00:00      
                                 Why should I insert a resistor in the GND line??            01/01/70 00:00      
                                    Seldom andonly if it is of benefit            01/01/70 00:00      
                                       No disagree, but ...            01/01/70 00:00      
                                          The regulator can't pull the Vcc down            01/01/70 00:00      
                                             This has nothing to do with imbalance!            01/01/70 00:00      
                                                Kai, I don\'t disagree ...            01/01/70 00:00      
                                                   Again, do not add any impedance in the GND line            01/01/70 00:00      
   tantalum capacitor across the MAX232 power pins            01/01/70 00:00      
      It's a matter of careful choice            01/01/70 00:00      
      Yes they does            01/01/70 00:00      

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