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???
05/19/07 14:11
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 		 #139517 - No need...
Responding to: ???'s previous message
Chinmay said:
To achieve a good resolution and accuracy we thought it would be better to separate the digital ground of microcontroller with that of the DAC since the fast switching characteristics of the digital section can induce noise in the DAC.

If you carefully read the datasheet and have a look at the evaluation board at the end of datasheet, then you will notice, that optos aren't needed to achieve highest performance.

Chinmay said:
What is the need to place inverter IC 74HC14 between DAC and my isolator?

74HC14 is not only an inverter, but more a Schmitt trigger! In combination with an opto it helps to restore the edges at output of opto, when a rather high ohmic pull-up (10k instead of 330R) is used to save supply current.


Kai

List of 37 messages in thread
TopicAuthorDate
need for isolating signals            01/01/70 00:00      
   avoiding the inverter            01/01/70 00:00      
      sinking the current            01/01/70 00:00      
         Sinking and sourcing            01/01/70 00:00      
            the bulb blinked !!!            01/01/70 00:00      
               Don't guess!            01/01/70 00:00      
                  trnasfer char.            01/01/70 00:00      
                     Transfer characteristic            01/01/70 00:00      
   More so            01/01/70 00:00      
   I see two possibilities            01/01/70 00:00      
      accuracy            01/01/70 00:00      
         0.01% approx 14 bits            01/01/70 00:00      
         Hardly...            01/01/70 00:00      
   No need...            01/01/70 00:00      
      need to place inverter            01/01/70 00:00      
      my design            01/01/70 00:00      
         FRC?            01/01/70 00:00      
            FRC?            01/01/70 00:00      
               or may be this......            01/01/70 00:00      
                  Not really            01/01/70 00:00      
                  Flat Ribbon Cable connector            01/01/70 00:00      
               FRC Connector!            01/01/70 00:00      
            You don't know the Flat Ribbon Cable?            01/01/70 00:00      
               Not by that name!            01/01/70 00:00      
         FAQ: How to post pictures?            01/01/70 00:00      
         you are grasping for straws            01/01/70 00:00      
         sure, but to what use            01/01/70 00:00      
         grounds etc            01/01/70 00:00      
            not entirely correct            01/01/70 00:00      
               single plane            01/01/70 00:00      
                  A very well qualified layout person can do 'magic'            01/01/70 00:00      
                     but he can hardly outsmart the laws of physics            01/01/70 00:00      
                  Nevertheless, there IS a difference            01/01/70 00:00      
                     the difference            01/01/70 00:00      
                        Yes, yes, yes, but...            01/01/70 00:00      
   Aside: Other Isolation Technologies            01/01/70 00:00      
   no response            01/01/70 00:00      

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