• State Not Answered
  • Replies 1 reply
  • Subscribers 38 subscribers
  • Views 331 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    









		











	
	
			
	
			
		
	
	
		

		
LT3094 unknown output



		

			

									
						nocturnalpea
					
							

			
				
									
											
							 		
		        	            							
			
			    	
			                    
                
				                on Dec 10, 2019 
				
			
			
		


				
		

		    		    
		    
		    	
			
Hi,


I'm currently having an output issue that I hope someone can shed some light on.


I have the LT3094 connected with the following:


GND: pins 6 (ILIM), 9 (GND)
VIN (@ -15V): pins 1 (IN), 2 (IN), 3 (EN/UV), 5 (PGFB), and 13 (Exposed Pad)
PG: NC (floating)
VOUT: pins 10, 11, 12
VIOC: NC (floating)
SET: pin 8 is set to 130.5kohm (for -13.5V Vout)


** all recommended caps are also in place **


Please see the LTSPice picture. According to ltspice output as well as the datasheet pin definitions and connection info, I was expecting to see -13.5V on my lab circuit.


However, what I'm measuring is -5.999V (-6V) at Vout(?).


There is no overheating of the IC - my only guess/possibility is that the thermal shutdown is tripping.


Suggestions?




Thank you. 
RW. 

								


				
				
		

			
						
									
									
						
						
			
			
			
			
		


					

			





	

		
	















	

	

					



			


				
	









	
    
	

  • 
	
    



	
		
	
	



    
	
    
		
    
							
					
    
		
    
			
													0
							
			
				
									
							        
            
                                                                                                        
      
                            
    • 
                                 Analog Employees 
                                
                            
      • 
                        
     
                                                           			
			                            
                        
                on Dec 13, 2019 1:25 AM
            
            
					
    
	
    

		
		
    
					
    Hi,
    

    Can you show the waveform you're getting on the output with -6V to see and determine if it really is a thermal shutdown or for any possible reasons. It will be easier to decipher if you can provide us with waveform.
    One way to also check if there is a fault on your circuit is by putting a pullup resistor on your PG pin, if fault is detected PG should be low.
    

    thanks!
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

    •