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AD8421 Recommended for New Designs
The AD8421 is a low cost, low power, extremely low noise, ultralow bias current, high speed instrumentation amplifier that is ideally suited for a broad...
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AD8421 on Analog.com

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Using different values for +Vs and -Vs for AD8421

		
	
				

			

									
					    Sardis
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 9, 2014 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    Hello everyone,
    
 
    I have a question regarding AD8421. Is it OK to use two power supplies with different magnitudes for +Vs and -Vs? For example a -2.5V for -Vs and 5V for +Vs. How would it affect the operation of the part?
    
 
    Thanks
    
			
    
			
									
		                             
                        

    
    
                                            
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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 10, 2014 7:23 PM
            
            
						
			            		
      
		
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      Hello Sardis,
      
 
      It is fine to use asymmetrical power supplies to power the AD8421. Just keep in mind that the difference between the two supply voltages must be greater than the minimum supply voltage (5V) and less than the maximum supply voltage (36V). For your example, there is a 7.5V difference, which is okay.
      
 
      Also, don't forget the common-mode voltage limitation shown in figures 10 through 13 of the AD8421 data sheet. The AD8421 requires a couple of volts of headroom from the supplies, which limits the output range on small supplies. You may have to increase the supply voltages in order to get the desired output range.
      
 
      Best regards,
      
 
      Scott
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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                on Aug 2, 2018 10:32 AM
            
            
						
			            		
        
		
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        This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

        Thank you,
        EZ Admin
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
				
						
						
				
				
		
		
        
			
		
        
	
        

        

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