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ADuM4160 breaks/burns



		

			

									
						schoenf
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Aug 25, 2021 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
     
    

    This is our USB interface to a PIC32MX microcontroller. Left side is powered by USB, right side with 5 V. We use this design since some years and never had problems with it. But the last few weeks, we encounter that some ADuMs get very hot and don't work or even burn and break their package. Any idea, whether this is a bad batch or something is out of spec? Photo of PCB assembly with a broken IC below ...
    

    

     
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

					
    
			
    


    

	















    
	
    
	
    
					



			








	
	
	
	



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													+1
							
			
				
									
							        
			
			
			
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                on Aug 25, 2021 3:32 PM
            
            
					
      
	
      

		
		
      
					
      Hi Schoenf,
      

      

      Can you provide any additional information about whether the operating conditions would have changed in some way recently?
      

      Reviewing your schematic, I can say that unfortunately the design does have the ADuM4160 operating out of specification, beyond the absolute maximum ratings in fact for SPD and SPU pins. They are connected to VBUS1/VBUS2 = 5V, when the max allowed voltage is VDD1/VDD2 + 0.5V (VDD1/VDD2 are 3.3V).
      

      Best regards,
      

      Conal
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
        
            
			                            
                        
                on Aug 25, 2021 4:09 PM
            
            
												
						in reply to ConalW
					
									
        
	
        

		
		
        
					
        You're right! I just figured this out by myself some minutes ago. It is not my design but copy&pasted since some generations of PCBs and never led to a problem. Until now. We will change this! Thank you, anyway!
        

        

        Greetings
        

        Jochen
        
			
        

		
		
		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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