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HMC447 Recommended for New Designs
The HMC447LC3 is a low noise Divide-by-4 Regenerative Divider utilizing InGaP GaAs HBT technology. This wideband divider operates with input frequencies...
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HMC447 on Analog.com

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oscillation of HMC447



		

			

									
					    huahua001
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Aug 26, 2022 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  HMC447 
    
    		        		    		    	
			
    Hi all,
    

        The hmc447 is not working properly on my board when 26G input and 5V power are well supplied,there is a large signal output at 5Ghz around when i checked the output.And the signal is hung and moved which is like self-oscillation.What's worse, the part will no longer work normally when this happen.That menas i have to replace it with a new part if i want to get to work properly.
    

    I have some questions about  hmc447:
    

    1.Does it need a DC-blocked capacitor when there is  a hmc519 before hmc447? i see the output of hmc519 is DC blocked internally from the datasheet,so i didn't add a dc capacitor at the input in my design.
     
    

    2.when the hmc447 worked abnormally,i checked the input impedance of hmc447 which is 1.5 ohm instead of 50 ohm.Which may cause this happen?
    

    

    Thanks.
    

    

    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 hardware
                
                                                    
                 hmc447
                
                                                    
                 Frequency Dividers  Prescalers  and Counters
                
                                                    
                 Frequency Dividers  Multipliers  and Detectors
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
			                            
                                                                                                                        
            
				
			
            
					
      
	
      

		
		
      
					

      Hi,  It sounds to me like the input experienced electrical overstress.  The ESD rating on this device is not very high either (class 1A).  It could be that this was an ESD event during assembly.  Or it could be due to some interaction with the HMC519 after assembly.  It would be a good idea to send the bad unit into ADI's failure analysis and see if they can distinguish the failure mode.  To do this you would need to contact your local sales support to start this process.  
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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