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ADA4841-1 Production
The ADA4841-1 is a unity gain stable, low noise and distortion, rail-to-rail output amplifier that has a quiescent current of 1.5 mA maximum. In spite...
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ADA4841-1 on Analog.com

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Re: Driving ADC, please help



		

			

									
					    ADIApproved
					
							

			
				
									
											
			
			
				
  •  Analog Employees  

			
			
			    	
			                    
                
				                on Aug 15, 2013 
				
			
			
		


				
		

		    		    
		    
		    	
			
Hi Ramon,

 
You could use a basic inverting opamp config with the ADA4841-1

 
http://www.analog.com/static/imported-files/tutorials/MT-213.pdf

 
Rin would be twice Rf. You could use 5V and ground as the supplies. However the limitations are you may lose some range near ground and near 5V (maybe 50-100mV depending on head/footroom spec). Also the input impedance is dictated by Rin, so not a high impedance input. Is the positive supply fixed at 12V?

 
Best Rgds,

 
Alan

								


				
				
		

			
						
									
									
						
						
			
			
			
			
		


        
        

					

			






	

		
	

















	

	

					



			








	
	
	
	



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    •  Analog Employees  
    
            
			                            
                        
                on Aug 22, 2013 5:50 PM
            
            
					
    
	
    

		
		
    
					
    Hi Ramon,
    
 
    The solution i described is a single supply solution. You use a 5V supply for Vs+ and connect the Vs- to ground. Because of the inverting config you have a resistor from the 10V to virtual ground on the opamp so the opamp itself does not see 10V.
    
 
    Best Rgds,
    
 
    Alan
    
 
    Edit: Sorry Ramon, an important piece of info I left out is that you will need to bias the + input of the opamp at 2/3 of the output range or 3.33V in order to level shift the opamp output. This could be achieved with a 2:1 resistor divider from the 5V reference. In terms of stability see this RAQ
    
 
    http://www.analog.com/static/imported-files/rarely_asked_questions/RAQ_attenuator.pdf
    
 
    Message was edited by: Alan Walshe
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
			                            
                        
                on Aug 22, 2013 5:50 PM
            
            
					
    
	
    

		
		
    
					
    Hi Ramon,
    
 
    The solution i described is a single supply solution. You use a 5V supply for Vs+ and connect the Vs- to ground. Because of the inverting config you have a resistor from the 10V to virtual ground on the opamp so the opamp itself does not see 10V.
    
 
    Best Rgds,
    
 
    Alan
    
 
    Edit: Sorry Ramon, an important piece of info I left out is that you will need to bias the + input of the opamp at 2/3 of the output range or 3.33V in order to level shift the opamp output. This could be achieved with a 2:1 resistor divider from the 5V reference. In terms of stability see this RAQ
    
 
    http://www.analog.com/static/imported-files/rarely_asked_questions/RAQ_attenuator.pdf
    
 
    Message was edited by: Alan Walshe
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
				
						
				
				
		
		
    
			
		
    
	
    

    

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