Products In This Thread

LT1790 Production
The LT1790 is a family of SOT-23 micropower low dropout series references that combine high accuracy and low drift with low power dissipation and small...
Datasheet
LT1790 on Analog.com

  • Replies 1 reply
  • Subscribers 2 subscribers
  • Views 359 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    




















	
	
			
	
		
		
	
	
		

		
LT1790 Vout-2.5V



		

			

									
					    b.bosquet
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 5, 2021 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Dear support team, 
    

    I have a few questions regarding LT1790 to output -2.5V. 
    

      

    1. In figure 7, R1 is set to 10k for a 3V input. Must we adjust resistor value for higher input voltages (5V input for example)? 
      2. 

    2. In figure 7 considering RL=20k, Vee=-5V, Vin = 5V. How can we estimate the maximum load on -2.5V output? In LTspice simulation loading -2.5V with a 20k resistor drops -2.5V output ref to -2.14V  
      3. 

    

    Thank you. 
    

    Benoît 
    

    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	















    
	
    
	
    
					



			


				
	









	
      
	

    • 
	
      






      
	
      
		
      
							
					
      
		
      
			
											
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Jan 6, 2021 1:21 PM
            
            
					
      
	
      

		
		
      
					
      Hi Benoit,
      

        

      1. Yes. The purpose of the resistor is to limit the current flowing in, but still biasing some other parts of the system. If you increase the Voltage input and still use 10k resistor, this will cause the pnp transistor from the output pin to turn on.
        2. 

      2. The equation given seems to be incomplete. The complete equation should be: R=(VEE-Vout)/(125uA+Iout)
        3. 

      

      

      Regards,
      

      Mon
      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
				
						
				
				
		
		
      
			
		
      
	
      

      

      •