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Questions about the current consumption of the LTM8054 at no load



		

			

									
					    knj
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Aug 27, 2019 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi,
    

    I have a few questions about the LTM8054.
    

    In the LTM8054, a current consumption of about 200mA flowed despite no load.
    There was also a slight device heat generation.
    

    

    

    This occurred in the circuit diagram described in data sheet P23.
    

     
    

    

    

    As a countermeasure, by adding a 0.01uF capacitor between the LL-MODE pin and GND, 
    

    the current consumption was improved and heat generation was reduced.
    

     
    

    【Questions】
    

    １．Is there any problem in adding the capacitor? (Including capacitor value)
    

    　　Please let me know if there are other good measures.
    

    ２．Do the same symptoms occur with LTM8055 and LTM8064?
    　　The same symptom does not occur while using it now.
    　　Is there any countermeasure for each device?
    

    

    

    I would appreciate your answer.
    

    Best Regards.
    

    

    

    

    

    

    

    

    

    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
			                            
                        
                on Aug 30, 2019 7:27 AM
            
            
					
      
	
      

		
		
      
					
      Hi I'm an FAE working closely with the questioner. By what is described in his question it looks FCM accidentally kicks in when not usingthe  0.01uF cap?.  I myself could not find clear expalation on the nesessity of the cap, or the difference in terms of the cap between the circuits appear in pate 23 and 24 in the datasheet   . Woudl you be able to help out? Also, They are worrying the same applies to the LTM8055. 
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
			                            
                        
                on Sep 5, 2019 8:32 AM
            
            
					
      
	
      

		
		
      
					
      Hi 
      

      On page 16 under "Switching mode" of LTM8054 datasheet, When mode and LL are connected together it is actually suggested to add ~0.1µF between this pins and ground to improve the light load transient response by delaying the transition from the discontinuous to forced continuous switching modes.
      

      This is the same with LTM8055
      

      Regards, 
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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