Products Mentioned

LT3467A Production
The LT3467/LT3467A switching regulators combine a 42V, 1.1A switch with a soft-start function. Pin compatible with the LT1930, its low VCESAT bipolar switch...
Datasheet
LT3467A on Analog.com

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lt3467a

		
	
				

			

									
					    Vania
					
							


			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Apr 9, 2020 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    Hello,
    

    

    I'm trying to use lt3467A in sepic configuration. Using ltspice, it seems possible, but my prototype does not work
    

    

     
    

    

     
    

    

    Where is my error?
    

    

    Thankyou
    

    

    Best Regards
    
			
    
			
									
		                             
                        

    
    
                                            
                 Step-Up (Boost) Regulators
                
                                                    
                 LT3467A
                
                                                    
                 Internal Power Switch Boost Regulators
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                                                    
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Apr 9, 2020 11:48 AM
            
            
						
			            		
      
		
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      Hi, 
      

      The error has to be in your hardware, as the simulation should run fine modeled as the schematic you're posting.
      

      There is just one problem with your simulation: even though it runs fine, the switch current is too high. For a 5V input and an 8V output the guaranteed switch current is very close to 1A.
      

      If you really need about 270mA, as suggested in the simulation, you need to use 2.2uH coupled inductors (both windings on the same core), or increase both inductors to 4.7uH.
      

      Or, simply reduce your load.
      

      That however, will not fix the hardware issue.
      

      Best Regards,
      

      DV
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
				
				
				
		
		
      
			
		
      
	
      

      

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