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AD7794 External Voltage



		

			

									
					    cevdet29
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 28, 2018 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello 
    

    I want to use an external voltage of 3.3V for AD7794 to fully capture the signal.
    

    Which voltage reference component you suggest me to choose?
    

    And should I connect the REFIN- pin to the GND? 
    

    

    Thank you.
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			


				
	









	
      
	

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													+1
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Dec 5, 2018 1:25 PM
            
            
					
      
	
      

		
		
      
					
      This was answered on another thread, so i copied it and pasted it below.
      

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      Hi cevdet29,
      

      The AD7794 suggests the use of ADR391 and ADR381 which are 2.5 V micropower low noise voltage reference.
      

      For 3.3V, I suggest you use the ADR4533 which is ultra-low noise but has Is=950uA compared to the ADR391 with Is=120uA.
      

      Yes you can connect the REFIN- pin to GND.
      

      Btw the external reference can only accept 3.3V when AVdd is powered at 3.3V
      

      Hope this helps.
      

      ACatapang
      

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