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The ADCMP606 and ADCMP607 are very fast comparators fabricated on XFCB2, an Analog Devices, Inc., proprietary process. These comparators are exceptionally...
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ADCMP607 on Analog.com

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ADCMP607 - why example circuits have external 50R pull ups?



		

			

									
					    m3atwad
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 20, 2018 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello,
    

    

    Why does the data sheet show internal 50R pullups as part of the CML outputs as shown below:
    

     
    

    

    But in the example circuits each one has external 50R pullups on the output.  Are you required to use the external 50Rs?  This will be driving 50R transmission lines to another CML input.
    

     
    

    

    Any guidance is greatly appreciated!
    

    

    Thanks!
    
									
			        
		
    

				
						
        

    
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													+1
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                                                                                                                        
            
				
			
            
					
      
	
      

		
		
      
					
      Hi,
      

      No need for this pull up if your circuit will be connected to a CML input receiver with an internal pull up of 50 Ohm, and yes it is correct to have a 50ohm line impedance.
      

      If in case your CML receiver does not have an internal 50 Ohm pull up, you can use a 50 Ohm pull up near the input of your CML receiver with still, 50Ohms line impedance.
      

      Both condition will enable proper line termination.
      

      

      Regards,
      

      joven
      

      

      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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    • 
	
      



	
			
		
	



      
	
      
		
      
							
					
      
		
      
			
													+1
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                                                                                                                        
            
				
			
            
					
      
	
      

		
		
      
					
      Hi,
      

      No need for this pull up if your circuit will be connected to a CML input receiver with an internal pull up of 50 Ohm, and yes it is correct to have a 50ohm line impedance.
      

      If in case your CML receiver does not have an internal 50 Ohm pull up, you can use a 50 Ohm pull up near the input of your CML receiver with still, 50Ohms line impedance.
      

      Both condition will enable proper line termination.
      

      

      Regards,
      

      joven
      

      

      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

      • 


    


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