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The ADG726/ADG732 are monolithic, complementary metal oxide semiconductor (CMOS) 32-channel and dual 16-channel analog multiplexers. The ADG732 switches...
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ADG726 on Analog.com

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Negative differential analog signal inputs with Single Power Supply



		

			

									
					    MEY007
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 28, 2025 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  ADG726  
    
    		        		    		    	
			
    Hello,
    

    would it be possible to input into the multiplexer a negative differential voltage signal (from a thermoucouple measuring low negative voltages : mVs) even though it is powered by a single power supply (Vdd +5V and Vss=GND) ?
    

    I know that in the specs the input analog signal qhould be between 0 and VDD :
    

     
    

    but the the maximum rating  allows -0.3 Vss:
    

     
    

    

    Would multiplexing thermoucples with negative voltages as low as -10mVs be an issue in Single Suply power ?
    

    

    Thank you in advance for your help !
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Dual-Supply Analog Switches and Multiplexers
                
                                                    
                 hardware
                
                                                    
                 adg726
                
                                                    
                 Analog Switches Multiplexers
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 29, 2025 8:42 PM
            
            
					
      
	
      

		
		
      
					
      Hi  ,
      

      Please note that the signal range of the ADG726 at a negative supply can reach as low as -0.3 V due to the internal protection diodes, even when it is used in a single supply configuration.

      Could you confirm if -10 mV is the maximum? If so, that would be acceptable.

      Best regards,
      Christian
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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                on Jan 31, 2025 5:24 AM
            
            
												
						in reply to Christian
					
									
        
	
        

		
		
        
					
        Hello Christian,
        

        

        Thank you for your quick response !
        

        Yes i can confirm to you that itw won't exced the -10mV.
        

        And I have another question please in this scope:
        

        I'm planning to use this multiplexer in a circuit similar to the one in the CN0354 evaluation board (instead of using the ADG1609 mux I'll use the ADG726):
        

         
        

        However I don't understant why there is no anti alyasing filter and a buffer at the input of the mux (between the thermocouples and the mux).
        

        wouldn't that reduce the kickback effect due to the mux and also filter out the input ?
        

        It would be very kind of you to clarify that.
        

        

        Thank you in advance !
        

        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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