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ADuM1447 Recommended for New Designs
The ADuM1440/ADuM1441/ADuM1442/ADuM1445/ADuM1446/ADuM1447 are micropower, 4-channel digital isolators based on the Analog Devices, Inc., iCoupler® technology...
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ADuM1447 on Analog.com

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ADuM144X creepage distance



		

			

									
					    AndredjV
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Sep 15, 2016 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    We have a problem with one of your isolators ADuM1447 where from the datasheets package drawing the cheepage distance for the part is 5.6mm (enaugh for our purpose) but in the VDE report its stated 5.3mm (does not comply to standard in our case). Where is the error in your datasheet or in VDE report?
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Digital Isolation Technology
                
                                                    
                 adum1447
                
                                                    
                 Standard Digital Isolators
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Sep 16, 2016 12:58 PM
            
            
					
      
	
      

		
		
      
					
      Hello;
      
 
      I always defer to the agencies measurements.  5.6mm on the drawing is the maximum body width under the JEDEC package standard. The drawing also says it could be as small as 5.0mm. 
      
 
      Unfortumately due to the way that JEDEC spedcifies their packages.  The creepage can not be reliabley determined from the drawing.  JEDEC tends to dump all of the packge tollerances onto the path that is required for creepage.  For example, there is no spec for the distance from the end pin to the end of the package .  In addition, there is a floating metal tie bar, that is required as part of the package manufacturing process, that must be subtracted from the creepage since it is right in the path.  Not problems for most products, but in isolation, it directly impacts the creepage.  So the agencies actually measure the package.  CSA measures 5.1mm, VDE measures 5.3.  Table 13 in the data sheet calls out 5.1 so we cover the worst case.
      
 
      For your issue, have you taken into account that our Mold compound is material group II.  That usually reduces the required creepage by about 33%.
      
 
      Best Regards,
      
 
      MSCantrell
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Sep 16, 2016 12:58 PM
            
            
					
      
	
      

		
		
      
					
      Hello;
      
 
      I always defer to the agencies measurements.  5.6mm on the drawing is the maximum body width under the JEDEC package standard. The drawing also says it could be as small as 5.0mm. 
      
 
      Unfortumately due to the way that JEDEC spedcifies their packages.  The creepage can not be reliabley determined from the drawing.  JEDEC tends to dump all of the packge tollerances onto the path that is required for creepage.  For example, there is no spec for the distance from the end pin to the end of the package .  In addition, there is a floating metal tie bar, that is required as part of the package manufacturing process, that must be subtracted from the creepage since it is right in the path.  Not problems for most products, but in isolation, it directly impacts the creepage.  So the agencies actually measure the package.  CSA measures 5.1mm, VDE measures 5.3.  Table 13 in the data sheet calls out 5.1 so we cover the worst case.
      
 
      For your issue, have you taken into account that our Mold compound is material group II.  That usually reduces the required creepage by about 33%.
      
 
      Best Regards,
      
 
      MSCantrell
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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