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ADF4156 Production
The ADF4156 is a 6.2 GHz fractional-N frequency synthesizer that implements local oscillators in the up-conversion and down-conversion sections of wireless...
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ADF4156 on Analog.com

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ADF4156 Design Issue at 1911.642 MHz



		

			

									
					    humayunzahid
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on May 1, 2014 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello!
    
 
    I've been using ADF4156 to design Local Oscillators at frequencies in the range of 5 to 6 GHz.
    
 
    I use ADISimPLL and Fraction N software for the design.
    
 
    I haven't faced any difficulties in the LO design at the above mentioned frequencies; but, i am facing difficulties in designing a LO at 1911.642 MHz. 
    
 
    The LO worked fine initially, but, strangely enough, it stopped working afterwards.
    
 
    The charge pump output voltage is at 0.4V to 0.5V no matter what register configuration i use.
    
 
    Further, the PLL chip gives out 5V at the charge pump out if i only enable the charge pump supply.
    
 
    I've also designed a test PCB of ADF4156, but the PLL chip responds the same way.
    
 
    Kindly help me in resolving this issue.
    
 
    Am i programming the chip wrong?
    
 
    It should not be the case as the LO was working initially.
    
 
    An example for designing the LO at 1911.642MHz using Fraction N software and ADISimPLL would be highly helpful.
    
 
    Thanking you in anticipation.
    
 
    With best regards,
    
 
    Humayun Zahid
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 adf4156
                
                                                    
                 Fractional-N PLL
                
                                                    
                 Phase Locked Loop (PLL) Synthesizer & Translation Loop
                
                                                    
                 rf and microwave
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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                on May 13, 2014 12:28 PM
            
            
					
        
	
        

		
		
        
					
        Hi Brigid!
        
 
        The question was originally posted by me.
        
 
        A channel spacing of 2 KHz was used and Z-Com V674ME08 VCO was used.
        
 
         The design issue has been resolved; the problem was with the prescaler value; i was using 8/9 instead of 4/5.
        
 
        I use Windows 7, and the AD's Fractional N software wasn't showing an error on using the 8/9 prescaler below 3 GHz.
        
 
        But, strangely enough, the LO was working previously when i used the 8/9 prescaler.  
        
 
        So, this question still remains un-answered as to how it was working by using a prescaler of 8/9 (provided all the other settings were same). 
        
 
        thanks for your support.
        
 
        with best regards,
        
 
        Humayun Zahid
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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													0
							
			
				
									
							        
			
			
			
          
            
						
                            
            
            				
            
                on May 13, 2014 12:28 PM
            
            
					
          
	
          

		
		
          
					
          Hi Brigid!
          
 
          The question was originally posted by me.
          
 
          A channel spacing of 2 KHz was used and Z-Com V674ME08 VCO was used.
          
 
           The design issue has been resolved; the problem was with the prescaler value; i was using 8/9 instead of 4/5.
          
 
          I use Windows 7, and the AD's Fractional N software wasn't showing an error on using the 8/9 prescaler below 3 GHz.
          
 
          But, strangely enough, the LO was working previously when i used the 8/9 prescaler.  
          
 
          So, this question still remains un-answered as to how it was working by using a prescaler of 8/9 (provided all the other settings were same). 
          
 
          thanks for your support.
          
 
          with best regards,
          
 
          Humayun Zahid
          
			
          

		
			
	      

		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

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