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LTM8078 RUN Pin Input Impedance



		

			

									
					    RobertT
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 23, 2022 
				
			
			
		
    

				
		
    
		    		    
		    
		    		            		        
    Category: Datasheet/Specs
    
    		        		            		    
    Product Number:  LTM8078 
    
    		        		    		    	
			
    Hello,
    

    What is the input impedance of the RUN pin on the LTM8078 regulator? I'd like to know it's current draw for different voltages.
    

    In the datasheet, I see that the "RUN Input Current" is listed as 1uA, but the condition for that is "RUN = 0V".  I'm not sure what that means.
    

    

    Thank you!!
    

    Robert
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		
	
    















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
			                            
                        
                on Nov 24, 2022 1:09 AM
            
            
					
      
	
      

		
		
      
					
      Hello,
      

      We dont have the RUN pin current drawn data but the fact that RUN pin can be tied to VIN which is up to 40V means that RUN should be a high impedance pin. There is also an existing LTSpice model for the part so you could try and simulate this.
      

      Regards,
      

      Nino
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
        
            
			                            
                        
                on Nov 24, 2022 1:19 AM
            
            
												
						in reply to NinyoP
					
									
        
	
        

		
		
        
					
        Agreed, but if you are controlling RUN with a resistive divider, it could make a difference. "High impedance" is subjective.
        

        Anyway, I think I found an alternate solution, but it would be interesting to know. Maybe RUN pin impedance can be added to the next rev of the datasheet (someone must know if they made a SPICE model for it).
        

        In any case, thank you for the reply!!
        

        Robert
        
			
        

		
		
		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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