Products Mentioned

LT1990 Recommended for New Designs
The LT1990 is a micropower precision difference amplifier with a very high common mode input voltage range. It has pin selectable gains of 1 or 10. The...
Datasheet
LT1990 on Analog.com

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LT1990

		
	
				

			

									
					    Sisamyo
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Jul 18, 2020 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hello,


It says isolated In data sheet. Can I put an other ground in non inverting input as a ground for feed current. How do the integrated inputs in the circuit look like ?

			

			
									
		                             
                        

    

                                            
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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jul 21, 2020 10:22 AM
            
            
						
			            		
    
		
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    Hi Sisamyo,
    

    Could you be more specific which part of the LT1990 datasheet that says isolated? If I understand it correctly, you want to ground the non-inverting input is that correct?
    

    For the last question, the LT1990 is an integrated difference amplifier as seen on the block diagram in the datasheet. The input resistor network composed by the 1M and 40k on chip resistor creates the internal common-mode voltage divider to allow the part to accept a wider input voltage range compared to the power supply used. 
    

    Thanks,
    

    Donnie
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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