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LTC3309B Recommended for New Designs
The LTC3309B is a very small, high efficiency, low noise, monolithic synchronous 6A step-down DC/DC converter operating from a 2.25V to 5.5V input supply...
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LTC3309B on Analog.com

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Regarding  Fsw 4MHz  Conducted noise

		
	
				

			

									
					    Kotaro
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 14, 2025 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  LTC3309B  
    
    		        		    		    
    
		    		    
		    			
    
			    
    I am operating in burst mode with Fsw : 4MHz.
    But , conducted noise on the input side shows a strong level at 2MHz.
    

    Can you please tell me why the signal can be confirmed at 2MHz? 
    

    Thanks
    

    Kotaro Suzuki
    
			
    
			
									
		                             
                        

    
    
                                            
                 hardware
                
                                                    
                 Micropower Buck Regulators
                
                                                    
                 LTC3309B
                
                                                    
                 Step-Down (Buck) Regulators
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                                                    
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 14, 2025 10:15 AM
            
            
						
			            		
      
		
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      What is the load? This might be the burst mode frequency for the load. Below is a scope shot of the LTC3309A burst mode. The burst mode for the 4MHz app will be different because different inductor and output caps are used. The burst frequency also changes with load, line and VOUT. The burst frequency can be observed by looking at the SW node and output ripple. 
      

       
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
				
				
				
		
		
      
			
		
      
	
      

      

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