Products Mentioned

ADM485 Production
The ADM485 is a differential line transceiver suitable for high speed bidirectional data communication on multipoint bus transmission lines. It is designed...
Datasheet
ADM485 on Analog.com

ADM485E Production
The ADM485E / ADM487E / ADM1487E are 5 V low power data transceivers with ±15 kV ESD protection suitable for half duplex communication on multipoint bus...
Datasheet
ADM485E on Analog.com

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Please ask what causes adm485 to fail to communicate?

		
	
				

			

									
					    Clark666
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Jan 21, 2021 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
1500 sets were produced, and about 80 sets could not be charged normally due to 485 IC problem,


The fault phenomena are as follows:


When the output current of power supply product reaches 30A or above,


Adm485 can not communicate, resulting in the output current of the power supply can not continue to adjust the current through adm485 communication,


After the power supply voltage of adm485 is increased to 4V, the communication is normal (at present, the power supply of adm485 is set to 3.3V)


However, after replacing the adm485 with a new adm485 IC, the power supply voltage is reduced to 3V, and the communication is OK




Please ask what causes adm485 to fail to communicate?



The schematic diagram is as follows:



			

			
									
		                             
                        

    

                                            
                 RS-232 / RS-422 / RS-485 / RS-562
                
                                                    
                 ADM485E
                
                                                    
                 adm485
                
                                                    
                 RS-485 and RS-422
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			


				
	









	
    
	

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                on Jan 21, 2021 7:10 AM
            
            
						
			            		
    
		
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    1500 sets were produced, and about 80 sets could not be charged normally due to 485 IC problem,
    

    The fault phenomena are as follows:
    

    When the output current of power supply product reaches 30A or above,
    

    Adm485 can not communicate, resulting in the output current of the power supply can not continue to adjust the current through adm485 communication,
    

    After the power supply voltage of adm485 is increased to 4V, the communication is normal (at present, the power supply of adm485 is set to 3.3V)
    

    However, after replacing the adm485 with a new adm485 IC, the power supply voltage is reduced to 3V, and the communication is OK
    

    

    Please ask what causes adm485 to fail to communicate?
    

    

    The schematic diagram is as follows:
    

     
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jan 25, 2021 6:10 AM
            
            
												
						in reply to Clark666
					
										
			            		
    
		
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    Hi Clark,
    

    The ADM485E is specified for a Vcc supply of 4.5-5.5V.  Is there any reason why your design cannot meet this specified range?
    

    We have a wide range of half duplex RS-485 transceivers that can operate at 3.3V supply ranges, For example the ADM3065E (3V to 5.5V) and ADM3078E (3 to 3.6V).
    

    Best Regards,
    

    Shane
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
						
						
				
				
		
		
    
			
		
    
	
    

    

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