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ADA4830-1 Recommended for New Designs
The ADA4830-1 (single) and ADA4830-2 (dual) are monolithic, high speed difference amplifiers that integrate input overvoltage (short-to-battery) protection...
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ADA4830-1 on Analog.com

ADV7180 Not Recommended for New Designs
The ADV7180 automatically detects and converts standard analog baseband television signals compatible with worldwide NTSC, PAL, and SECAM standards into...
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ADV7180 on Analog.com

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ADA4830-1 in pseudo-differential mode... input trace geometry?



		

			

									
					    MarkEP
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 20, 2015 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi,..I'm using difference amp ADA4830-1 in conjunction with decoder ADV7180 (Circuit Note CN-0263), to receive a CBVS video signal.  My question has to do with the ADA4830 input trace geometry on my circuit board.  Given that I'll be connecting the input as a pseudo-differential signal pair - should I route this input as 75 ohm diff trace pair, or 75 ohm single ended?
    
									
			        
		
    

				
						
        

    
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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Dec 1, 2015 3:19 PM
            
            
					
      
	
      

		
		
      
					
      Hi Mark,
      
 
      The input trace geometry on your circuit board can be 75 Ohm single ended.  I think that the trace impedance between the 75 Ohm load and the input of the ADA4830 should not have a large impact on system performance though, as these traces should be typically be kept quite short.  If this is not the case, please let me know and we can discuss further.
      
 
      Regards,
      
 
      Paul
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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                on Dec 1, 2015 3:43 PM
            
            
					
        
	
        

		
		
        
					
        Hi Paul,
        
 
        Thanks - I'd come to the same conclusion after further consideration. The signals are obviously not a true diff pair, with the primary reason for bringing the reference signal to the diff amp is, to as much as possible, reject any common mode influence on the video input. And I missed a major clue in the circuit diagram - the 75 ohm termination. A true diff pair would normally require a 150 ohm terminator.
        
 
        Thanks again for the input... 75 ohms SE it is.
        
 
        Mark
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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