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Noisest Opamp?



		

			

									
					    didymus7
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Feb 17, 2015 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			

    Now that I've got your attention...no, no, this is real.
    
 
    My company wants to sell into China without having to wait months for an export license, we can accomplish this by making the resolution of our systems worse, especially in the bandwidth below 100 Hz.  I know that FET amps tend to have the most noise down in that area, but what is the noisest one?  We have amps in the SOIC-8 package (duals).  I'm also going to sprinkle some carbon comp resistors in there to boost the noise. 
    
 
    I know that I can do a redesign to add a noise generator, but I'm trying to get around this without a redesign and re-layout.
    
 
    Thanks...Steve
    
								
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		
	
    















    
	
    
	
    
					



			








	
	
	
	



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                on Mar 7, 2015 7:23 AM
            
            
					
        
	
        

		
		
        
					
        Thanks much.  While I like the idea of the cap in series with R25, I'm going to have to do something without going through a board turn. For gain, I had planned to perhaps boost the gain at this stage and allow the later range adjustment stage work lower.  There is a log amp in-between, so there would be some linearity change.  My thought was to find an old FET opamp since those usually have bad low frequency noise.
        
			
        

		
		
		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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                on Mar 7, 2015 7:23 AM
            
            
					
          
	
          

		
		
          
					
          Thanks much.  While I like the idea of the cap in series with R25, I'm going to have to do something without going through a board turn. For gain, I had planned to perhaps boost the gain at this stage and allow the later range adjustment stage work lower.  There is a log amp in-between, so there would be some linearity change.  My thought was to find an old FET opamp since those usually have bad low frequency noise.
          
			
          

		
		
		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

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