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The ADR3412 / ADR3420 / ADR3425 / ADR3430 / ADR3433 / ADR3440 / ADR3450 are low-cost, low-power, high precision voltage references, featuring ± 0.1% initial...
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CN0357 Board with biased gas sensor  O2 3 Electrode



		

			

									
					    Sakaz
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jun 9, 2021 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi Forum, 
    

    I am new in this forum. I am considering to use attached CN0357 board to read Oxygen Sensor 3 Electrode. But the Biasing current required -600mV.  I have read in this fourm that i need to remove ADR3412 and give biasing voltage instead. my question is that should i give -600mV on this Vref pin. i would be pleased if you could guide me to solve the issue at this initial stage. 
    

    Thanks in advance. 
    

    

     
    
									
			        
		
    

				
						
        

    
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                 adr3412
                
                                                    
                 Series Voltage References
                
                                                    
                 voltage references
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jun 10, 2021 9:51 AM
            
            
					
      
	
      

		
		
      
					
      Hi Sakaz,
      

      I am assuming the question you read in the forum was the one using the 200mV bias. For your case using the oxygen sensor, the bias of -600mV actually means that the working electrode WE is 600mV lower than the reference electrode. You can still do this using this board with a single power rail. This means you will have to change the vref voltage to 600mV plus the virtual ground voltage (currently at 1.2V). You will also want to change the virtual ground voltage to be lower than 1.2V to make the output swing still centered. You can keep the ADC reference and negative signal input at 1.2V.
      

      You can check out the "biased sensor circuit with single supply" section in this article for more details: A1A-EC_SENSORS_AN2-Design-of-Electronics-for-EC-Sensors-V4.pdf (sgxsensortech.com)
      

      Regards,
      

      Nikko
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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