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ADF4356 Recommended for New Designs
The ADF4356 allows implementation of fractional-N or integer-N phase-locked loop (PLL) frequency synthesizers when used with an external loop filter and...
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ADF4356 on Analog.com

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ADF4356 freq vs volts



		

			

									
					    GlenEnglish
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 10, 2023 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  ADF4356 
    
    		        		        		        
    Software Version: -
    
    		    		    	
			
    Is there a Freq vs Volts chart for the VCO(s) like the ADF4351 for the ADF4356 ? I have not seen one.
    

    The reason to know this is that we only have 4.2V available for the VCOV, VPD  etc 
    

    We have about 20 in the field and it works fine on Vp= 4.2V.... VCO requirement is 6.3 GHz (fixed)  and currently Vtune is about 1.25V. I have never seen <1 or > 1.5....

    I am concerned that it might get itself into the > 4V region if it tries....
    

    Is there a demand for >=4.2V on VCOtune ? or is Vtune confined to lower levels ?
    board op temp = ~ 60 deg C.  Using automatic cal. 
    


    We have the ADF4356 EVAL. Very good. PLLsim is also a great tool, its why we buy ADI....

    regards, glen.
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 hardware
                
                                                    
                 adf4356
                
                                                    
                 Fractional-N PLL
                
                                                    
                 Phase Locked Loop (PLL) Synthesizer & Translation Loop
                
                                                    
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													+1
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 12, 2023 4:30 AM
            
            
					
      
	
      

		
		
      
					
      Hi Glen,
      

      The lower supply voltage (<4.75V) is not tested so I cannot make any exact commitment.
      

      I checked the validation data and the Vtune does not exceed ~3.5V. Vtune value is changing depending on the operational temperature and the temperature where autocal is done. It may drift a bit with aging in any direction as well. Again, please note that these tests are all for supply voltage >4.75V and <5.25V. 
      

      The phase noise might degrade a bit due to low supply voltage and probably low current.
      

      Regards, Kazim
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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                on Jan 12, 2023 5:04 AM
            
            
												
						in reply to kpeker
					
									
        
	
        

		
		
        
					
        Hi Kazim, thanks for the reply.
        Understood on 3.5V. Current is down from ~ 75mA at 5V to ~ 67mA. Not much drop , but we will keep an eye on it

        With many thanks,
        

        Background- I have 5.1V running around the board that drives switchers, LDOs etc, and the LDO we are using (everywhere)  for low dropout needs the bias voltage at least 0.7V above Vout... and so with 5V input, and 5V bias, the best I can do is 4.25V.  On the rev board, we put a 100mV dropout LDO there , and also kept the previous regulator if there are no problems.   .  BTW the chip meets the datasheet specs. very good. This device is about 6dB better than the ADF4351 narrow and wideband and I *think* its a quite a few dB better close in (1/f behaviour etc) . We are using it in integer mode to produce 393 MHz sample clocks for the AD9142 (1.6 Gsps)  and AD9634 (div2) 
        , push pull trasformer coupled output. lots of caps per pin.

        best regards
         
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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