Products Mentioned

HMC784A Recommended for New Designs
The HMC784AMS8GE is a high power SPDT switch in an 8-lead MSOPG package for use in transmit-receive applications which require very low distortion at high...
Datasheet
HMC784A on Analog.com

Thread Details

  • State Verified Answer
  • Replies 2 replies
  • Subscribers 69 subscribers
  • Views 297 views
  • Users 0 members are here
 
Related Content

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
HMC784AMS8GE: About RF and VDD using condition

		
	
				

			

									
					    Tomo-Kakehi
					
							


			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Aug 7, 2025 
				
			
			
		
    
		
		                    	    
    
        	    
    Thread Summary
    
                The user inquires about the potential cause of damage to the HMC784AMS8GE when an RF signal (0 dBm) is applied without Vdd. The final answer suggests that applying 0 dBm on the RF input with no power could cause damage, and emphasizes the importance of external ac-coupling on the RF pins, which is already provided on the customer evaluation board. The engineer also asks if logic levels were applied to the A and B inputs without power.
                        	    
    
                
                     AI Generated Content
                
    	    
    
             
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  HMC784AMS8GE, HMC784A 
    
    		        		    		    
    
		    		    
		    			
    
			    
    Hi,
    

    Our customer is using HMC784AMS8GE now.
    

    The HMC784AMS8GE was broken in below condition.
    

    Please tell me the cause of break if you know.
    

    Condition:
    

    Vdd = 8.2V
    

    Control A and B = 8.2V
    

    RF signal power = 0dBm
    

    

    He said it wonder if HMC784AMS8GE was input RF signal without Vdd.
    

    About situation, RF signal maybe has remained when Vdd turned off.
    

    Will this device be broken if input RF signal without Vdd?
    

    

    Best Regards,
    

    Tomohiro
    
			
    
			
									
		                             
                        

    
    
                                            
                 break
                
                                                    
                 hardware
                
                                                    
                 RF Switches
                
                                                    
                 HMC784AMS8GE
                
                                                    
                 sequence
                
                                        
                                            
                
                
                                        
                                            
                
                
                                
                    Show More
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                                                    
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

    • 
	
      



	
			
		
	



      
	
      
		
      
							
					
      
		
      
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Aug 7, 2025 4:11 PM
            
            
						
			            		
      
		
										+1
					
	
      

		
		
      
		
      
                                
                                                            
      
					
      Hi Tomohiro-San,
      it is possible that 0 dBm on the RF input with the power off could cause damage. Here is a test that they could do. Also, did they have the logic levels applied to the A and B inputs with the power not applied? 
      Are they working with their own board or with the customer evaluation board. It's important to note that the RF pins must be externally ac-coupled. if they are using the eval board, then this is ok because the eval board has capacitors on board. But if they are using their own boad without capacitors, that would be a problem. 
      Eamon 
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
				
				
				
		
		
      
			
		
      
	
      

      

      • 

	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
			
				
									
							        
			
			
			
        
            
						
                            
            
            				
            
                on Aug 7, 2025 10:47 PM
            
            
						
			            		
        
		
										0
					
	
        

		
		
        
		
        
                                
                                                            
        
					
        Hi Eamon-san,
        

        Thank you for prompt answer.
        

        I told to the customer that set sequence when power up and down.
        

        Best Regards,
        

        Tomohiro
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
				
				
				
		
		
        
			
		
        
	
        

        

        •