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LTC6268 Recommended for New Designs
The LTC6268/LTC6269 is a single/dual 500MHz FET-input operational amplifier with extremely low input bias current and low input capacitance. It also features...
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LTC6268 on Analog.com

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LTC6268 Spice Model and Noise Simulation

		
	
				

			

									
					    mspalluzzi
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Nov 6, 2024 
				
			
			
		

		
		                     
				
        		

		    
		    		    

		      		            		        
Category: Hardware

    		        		            		    
Product Number:  LTC6268  

    		        		    		    

		    		    
		    			

			    
Would a LTSpice noise simulation of the LTC6268 spice model accurately model the output noise of the device? Or are there missing elements to in the spice model required for an accurate noise analysis and I would be better off doing the calculation by hand?


My question is more about the spice model and less about LTSpice but here is my LTSpice circuit for reference:


 

			

			
									
		                             
                        

    

                                            
                 noise analysis
                
                                                    
                 Operational Amplifiers (Op Amps)
                
                                                    
                 ltc6268
                
                                                    
                 hardware
                
                                                    
                 High Speed Op Amps (Bandwidth = 50MHz)
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			


				
	









	
    
	

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Nov 6, 2024 8:59 PM
            
            
						
			            		
    
		
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    Hello ,

    I have done some noise simulations using the model and here are the results that I've obtained: 

     

     

    For the voltage noise, at frequencies less than about 60kHz, there is an observable difference between the simulated voltage noise vs. the actual voltage noise on the part's data sheet. On the other hand, at f > 60kHz, the simulated voltage noise density plot closely matches the actual plot.


     

     
    For the current noise, at frequencies below 10MHz, the simulated current noise closely matches the actual data from the data sheet. However, for f >10MHz, there is an observable difference between the simulated data and actual data.

    Based on the results above, I think you can still run some noise simulations, but I would also recommend correlating the simulated data with the calculated data and actual measured data.

    Best regards,
    Paul
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
						
						
				
				
		
		
    
			
		
    
	
    

    

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                on Nov 7, 2024 3:29 PM
            
            
												
						in reply to ADIApproved
					
										
			            		
    
		
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    Hi  
    

    Thank you very much for the response. That is very helpful and didnt think to try to recreate the datasheet plots and compare.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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