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LTC6957: self-bias voltage



		

			

									
					    tchu
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on May 12, 2022 
				
			
			
		
    

				
		
    
		    		    
		    
		    		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  LTC6957 
    
    		        		    		    	
			
    Hello,
    

    In LTC6957 datasheet, Inputs specifies "Vincm" which is the Self-bais voltage. I assume this is the common mode voltage.
    

    For LTC6957-2 (LVDS), can someone clarify why Vincm is set between 1.8V - 2.3V? Isn't LVDS calls for common mode voltage at 1.2V typical?
    

    Thank you
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
			                            
                        
                on May 13, 2022 2:10 AM
            
            
					
      
	
      

		
		
      
					
      The LTC6957-2 LVDS version refers to its output logic type (LVDS), the -1 has LVPECL outputs and -3/-4 have CMOS outputs..
      

      The LTC6957 input network/common is the same for all LTC6957 versions.  Page 22, figure 5 of the datasheet, shows how to AC-couple a LVDS signal to the LTC6957 input.  The Vincm spec sets the common mode of the AC coupled input signal to the correct input common mode level for optimized performance.
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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