Products Mentioned

LT1129 Production
The LT1129/LT1129-3.3/LT1129-5 are micropower low dropout regulators with shutdown. The devices are capable of supplying 700mA of output current with a...
Datasheet
LT1129 on Analog.com

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Simulation

		
	
				

			

									
					    Rami2
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Dec 4, 2025 
				
			
			
		

		
		                     
				
        		

		    
		    		    

		      		            		        
Category: Hardware

    		        		            		    
Product Number:  LT1129IS8TRPBF, LT1129 

    		        		    		    

		    		    
		    			

			    
Hi Team,
I simulated my circuit with Vin = 28 V and I need Vout = 15 V. 
I used R1 = 5 kΩ and R2 = 15 kΩ, but the output voltage is only 7 V.


 



I downloaded the two models from the link and built the circuit accordingly.
 


Regards,
Rami Reddy.

			

			
									
		                             
                        

    

                                            
                 LT1129IS8TRPBF
                
                                                    
                 hardware
                
                                                    
                 LT1129
                
                                                    
                 LDO Linear Regulators
                
                                                    
                 Positive Linear Regulators (LDO)
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                                                    
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			


				
	









	
    
	

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Dec 15, 2025 3:51 AM
            
            
						
			            		
    
		
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    Hi Rami,
    

    Thank you for reaching out to Analog Devices!
    

    For your application, please use the LT1129 rather than the LT1129-5. The LT1129 is the adjustable version, which allows you to set different output voltage levels as required. In contrast, the LT1129-5 is the fixed 5V output version.
    

      

    • LT1129 → Adjustable output
      • 

    • LT1129-5 → Fixed 5V output
      • 

    

    For your convenience, I’ve included the LTspice schematic and reference image in the link below:
    


    Please let me know if you have any further questions or need additional support.
    

    

    Thanks and Regards,
    

    Tech Support
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
				
				
				
		
		
    
			
		
    
	
    

    

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