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ADF4159 Recommended for New Designs
The ADF4159 is a 13 GHz, fractional-N frequency synthesizer with modulation and both fast and slow waveform generation capability. The part uses a 25-bit...
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ADF4159 on Analog.com

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PFD frecuency

		
	
				

			

									
					    AndresCes
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Oct 20, 2025 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  EV-ADF4159EB3Z 
    
    		        		    		    
    
		    		    
		    			
    
			    
    Hello, I want to generate a sawtooth output using the EV-ADF4159EB3Z board, connecting an external VCO operating from 1200–2300 MHz, specifically the CVCO55BE-1200-2300.
    

    The board includes a 100 MHz reference oscillator. In ADIsimPLL, I’m not able to select a divider to reach the operating frequencies I need (I used 50 MHz directly), although in the board’s control software I can do it.
    

    Is this actually the case? Can I use the EV-ADF4159EB3Z to generate frequencies within the 1200–2300 MHz range?
    

    Attached are some images to better illustrate the case.
       
    
			
    
			
									
		                             
                        

    
    
                                            
                 hardware
                
                                                    
                 rf & microwave
                
                                                    
                 Fractional-N PLL
                
                                                    
                 adf4159
                
                                                    
                 Phase Locked Loop (PLL) Synthesizer & Translation Loop
                
                                        
                                            
                
                
                                
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      •  Analog Employees  
      •  Super User  
      
            
						
                            
            
            				
            
                on Oct 21, 2025 3:14 AM
            
            
						
			            		
      
		
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      Hi, 
      

      In the ADISimPLL, you need to set the PFD frequency on the PLL Configuration. 
      

      Click File --> PLL Configurations, 
      

       
      

      Then, on this screen, set the PFD frequency and reference frequency. 
       
      

      Please note that since you are modifying the PFD frequency and using a different VCO that loop filter is desinged for, you need to simulate the loop filter with your VCO and PFD settings then implement it to the evaluation board. 
      

      

      Thanks,
      

      Emrecan
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
				
				
				
		
		
      
			
		
      
	
      

      

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                on Oct 21, 2025 11:25 AM
            
            
						
			            		
        
		
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        Yes, I simulated exactly as you said, but I wanted to know if it’s really possible to set 50 MHz and then use the divide-by-2 to get that phase detector frequency. I ran simulations with those settings—using the chosen VCO and the loop filter—and obtained the expected results.
         I just wanted to confirm whether it’s possible to use the 100 MHz reference and set the phase detector to 50 MHz.
        

        Andrés.
        

        

        

        

        

        

        

         
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
				
				
				
		
		
        
			
		
        
	
        

        

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