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LT1679 Production
The LT1678/LT1679 are dual/quad rail-to-rail op amps offering both low noise and precision: 3.9nV/vHz wideband noise, 1/f corner frequency of 4Hz and 90nV...
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LT1679 on Analog.com

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Replacement for MCP6004



		

			

									
					    wbadry
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Sep 23, 2019 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hello,
    

    I was using MCP6004 from Microchip and tried to replace it with LT1679 . Problem is I see the signal is noisy after replacing the MCP amplifier with the new LT selection. Is there any better alternative (Single and Quad amplifiers if possible)? Thanks 
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Operational Amplifiers (Op Amps)
                
                                                    
                 MCP6004
                
                                                    
                 amplifiers
                
                                                    
                 LT1679
                
                                                    
                 High Voltage Op Amps =12V
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      •  Super User  
      
            
						
                            
            
            				
            
                on Sep 25, 2019 5:19 PM
            
            
					
      
	
      

		
		
      
					
      Hi wbadry,
      

      What is your source impedance in this configuration where you replaced MCP6004 with LT1679 and got higher noise reading?
      

      If your input impedance is "high", you'd want to choose a device which has low current noise density. LT1679 input current noise density is higher than MCP6004. It is also a 20MHz part vs. 1MHz for MCP6004. So, it could be that you need to reduce your closed loop bandwidth to reduce excess noise beyond your freq range of interest.
      

      Here are some suggestions:
      

      Quad: LTC6082, LTC6088, or AD8648.
      

      Single: AD8615, or AD8605.
      

      

      Regards,
      

      Hooman
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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