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AD7788 Production
The AD7788/AD7789 are low power, low noise, analog front ends for low frequency measurement applications. The AD7789 contains a low noise, 24-bit, ?-?...
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AD7788 on Analog.com

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AD7788 increase the input range



		

			

									
					    Ocela
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 17, 2016 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Good day!
    Read of theme "AD7788: Input ranges"
    I have a question to the expert answer.  In documentation for REF3040 I found a similar circuit.
    
 
    A specialist in the above subject, a similar connection recommended AIN- input to expand the input voltage. However, in the specifications for REF3040 input voltage range has not changed. Where the error lies?
    
 
    Thank you!
    
									
			        
		
    

							
    
				
				
			
    
					
						
        

    
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                 Single Channel A/D Converters
                
                                                    
                 ad7788
                
                                                    
                 Precision A/D Converters
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Nov 20, 2016 1:34 PM
            
            
					
      
	
      

		
		
      
					
      Hi Ocela,
      
 
         As mentioned on the AD7788 datasheet it can have a unipolar and bipolar ranges. The Ain+ input can be referred to the Ain-. As an example, when using 2.5V on Ain-. The input voltage range is from 2.5V to 5V but when it is in bipolar mode the range will be from 0V to 5V. You can program the U/B bit in the mode register to select a unipolar /bipolar input. ADI has 2.5V reference voltage sources recommended like the ADR381 and ADR391. If you have other questions, please let us know.
      
 
      Regards,
      
 
      Jonathan
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Nov 20, 2016 1:34 PM
            
            
					
      
	
      

		
		
      
					
      Hi Ocela,
      
 
         As mentioned on the AD7788 datasheet it can have a unipolar and bipolar ranges. The Ain+ input can be referred to the Ain-. As an example, when using 2.5V on Ain-. The input voltage range is from 2.5V to 5V but when it is in bipolar mode the range will be from 0V to 5V. You can program the U/B bit in the mode register to select a unipolar /bipolar input. ADI has 2.5V reference voltage sources recommended like the ADR381 and ADR391. If you have other questions, please let us know.
      
 
      Regards,
      
 
      Jonathan
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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