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ADuM2251 Production
The ADuM2250 / ADuM2251 are hot swappable digital isolators with non-latching, bidirectional communication channels and are compatible with I2C interfaces...
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ADuM2251 on Analog.com

MAX1238 Production
The MAX1236–MAX1239 low-power, 12-bit, multichannel analog-to-digital converters (ADCs) feature internal track/hold (T/H), voltage reference, clock, and...
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MAX1238 on Analog.com

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ADUM2251 Side2 Slave don't respond



		

			

									
					    maximilian@stuttgart
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Feb 19, 2015 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello,
    
 
    I have a design (see Appendix), that makes some communication problems.
    
 
    I have double-checked logic low level thershold and it is more than 0,9V since 
    
 
    Vcc and Vcc-p is 5V.
    
 
    I have read this thread
    
 
    https://ez.analog.com/message/75240#75240
    
 
    and  I have also watched the Video from MSCantrell "How I2C Isolators work"
    
 
    Video which is super helpfull.
    
 
    When I use the digital Isolator for some reasons the MAX1238, don't pull down the data-line when
    
 
    it should transmit the data-pattern. With no digital isolator everything works fine.
    
 
    Has anybody an idea or hint ?
    
 
    Thanks for your support.
    
									
			        
		
    

							
    
				
				
			
    
					
						
        

    
    Tags: 
                                            
                 MAX1238
                
                                                    
                 Multiplexed A/D Converters
                
                                                    
                 Digital Isolation Technology
                
                                                    
                 adum2251
                
                                                    
                 Precision A/D Converters
                
                                        
                                            
                
                
                                
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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Feb 20, 2015 2:29 PM
            
            
					
      
	
      

		
		
      
					
      Hi Maximilian,

      There are a couple of questions I would like to ask before I can give a proper response.

      You have stated that the logic low level threshold is more than 0,9V this is occurring only on side 1 or side 2 of the ADuM2251? My initial guess is side 1 but I just wanted to make sure.
      
 
        
      
 
      The second question is do you have any scope screenshots of what you are seeing? A with and without isolator
      comparison would be nice. As well as a Side 1 and Side 2 snapshot as well.
      
 
      The last question is there some sort of communication going on at all? You mention that the MAX1238 doesn’t pull the data-line down but the details seem vague.
      
 
        
      
 
      Joseph Shim
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Feb 20, 2015 2:29 PM
            
            
					
      
	
      

		
		
      
					
      Hi Maximilian,

      There are a couple of questions I would like to ask before I can give a proper response.

      You have stated that the logic low level threshold is more than 0,9V this is occurring only on side 1 or side 2 of the ADuM2251? My initial guess is side 1 but I just wanted to make sure.
      
 
        
      
 
      The second question is do you have any scope screenshots of what you are seeing? A with and without isolator
      comparison would be nice. As well as a Side 1 and Side 2 snapshot as well.
      
 
      The last question is there some sort of communication going on at all? You mention that the MAX1238 doesn’t pull the data-line down but the details seem vague.
      
 
        
      
 
      Joseph Shim
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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