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ADA4927-1 Recommended for New Designs
The ADA4927 is a low noise, ultralow distortion, high speed, current feedback differential amplifier that is an ideal choice for driving high performance...
Datasheet
ADA4927-1 on Analog.com

ADA4927-1 Recommended for New Designs
The ADA4927 is a low noise, ultralow distortion, high speed, current feedback differential amplifier that is an ideal choice for driving high performance...
Datasheet
ADA4927-1 on Analog.com

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differential amplifier common mode output



		

			

									
					    saravadhamu
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Mar 31, 2011 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Dear sir, 
     We are using ADA4927-1 device for our application. In our application input to ADA4927-1 is form a sensor having  
    output in Differential mode. we want an output from ADA4927-1 in common mode configuration. we have gone through  
    the AN-584 APPLICATION NOTE and we uderstand that we need to give input to PIN No. 2 VOCM form a potential divider. 
    we request you to give the information  how to take output from ADA4927-1 in common mode ( ie What to do for one of the unused  
    pin No. 10 or 11 of ADA4927-1) and potential divider voltage to be  given to Pin. No. 2 of the Ada4927-1 for getting the common mode output. 
    
 
    please do the needful to me....
    
 

    
									
			        
		
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		
	
    















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
			                            
                        
                on Jul 29, 2011 8:36 PM
            
            
					
      
	
      

		
		
      
					
      You can compensate for the offset (and retain the dc component of your signal) with the circuit shown at the end of this email.
      
 
      Need the same RCM in both sides to retain balance. One RCM is usually grounded the other is connected to a reference voltage that will cancel input dc offset as well as the input offset of the diff-amp.
      
 
      The value of RCM is large compared to Rg.
      
 
      For Fixed compensation VREF can be VCC or VEE. In this case, you determine the input side that is at higher dc level and connect that RCM to ground. Apply a VREF to cancel out all nominal offsets.
      
 
      For dynamic compensation, VREF can come from a DAC. In this case the value of VREF is controlled dynamically. The dc offset is measured in the digital domain at some appropriate instant ( for example at power up) when the inputs are at a known “zero” state and a correction code is input to a DAC whose output is VREF.
      
 
      The accuracy of this correction can be made quite high if the value of RCM is high.
      
 
      Message was edited by: AndyR Removed Email Footer Information
      
			
      

		
			
	      

				
      
			
			
		
      
			
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Jul 29, 2011 8:36 PM
            
            
					
      
	
      

		
		
      
					
      You can compensate for the offset (and retain the dc component of your signal) with the circuit shown at the end of this email.
      
 
      Need the same RCM in both sides to retain balance. One RCM is usually grounded the other is connected to a reference voltage that will cancel input dc offset as well as the input offset of the diff-amp.
      
 
      The value of RCM is large compared to Rg.
      
 
      For Fixed compensation VREF can be VCC or VEE. In this case, you determine the input side that is at higher dc level and connect that RCM to ground. Apply a VREF to cancel out all nominal offsets.
      
 
      For dynamic compensation, VREF can come from a DAC. In this case the value of VREF is controlled dynamically. The dc offset is measured in the digital domain at some appropriate instant ( for example at power up) when the inputs are at a known “zero” state and a correction code is input to a DAC whose output is VREF.
      
 
      The accuracy of this correction can be made quite high if the value of RCM is high.
      
 
      Message was edited by: AndyR Removed Email Footer Information
      
			
      

		
			
	      

				
      
			
			
		
      
			
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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