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Use of TL431 for voltage reference of AD7683



		

			

									
						gigarashi
					
							

			
				
									
											
							 		
		        	            							
			
			    	
			                    
                
				                on Jan 12, 2017 
				
			
			
		


				
		

		    		    
		    
		    	
			
Hi,

 
I am interesting to use TL431 voltage reference to generate 5V to be used in Vref input of AD7683.

 
This voltage reference has low noise voltage enough for AD7683?

 
I am asking because many voltage reference devices inform noise voltage parameter, normally in a specific range of frequency and in micro volts.

 
For example, ADR435 device, from Analog: Low noise (0.1 Hz to 10.0 Hz): 3.5 µV p-p @ 2.5 V output.

 
Unfortunatelly, this information does not informed in the TL431 datasheet. I tried TI, OnSemi, etc...

 
Regards,

								


				
				
		

			
						
									
									
						
						
			
			
			
			
		


					

			





	

		
	















	

	

					



			








	
	
	
	



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							FormerMember
					
    
		
    
			
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									FormerMember
							        
            
                                    			
			                            
                        
                on Jan 13, 2017 12:28 AM
            
            
					
    
	
    

		
		
    
					
    I would not even consider the TL431 with a 16 bit ADC;  you are just throwing money away.
    
 
    The TL431 is a commodity reference, with 50 ppm/C tempco.  So after your temperature
    
 
    changes by 10 degrees, you have less than a 14 bit system.   There is a noise curve
    
 
    (fig 7) on the TI data sheet.   Integrate over your bandwidth.
    
 
    Depending on system cost target, look at the ADR3425 or the ADR4525 and everything
    
 
    in between.
    
 
    Harry
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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							FormerMember
					
    
		
    
			
													0
							
			
				
									FormerMember
							        
            
                                    			
			                            
                        
                on Jan 13, 2017 12:28 AM
            
            
					
    
	
    

		
		
    
					
    I would not even consider the TL431 with a 16 bit ADC;  you are just throwing money away.
    
 
    The TL431 is a commodity reference, with 50 ppm/C tempco.  So after your temperature
    
 
    changes by 10 degrees, you have less than a 14 bit system.   There is a noise curve
    
 
    (fig 7) on the TI data sheet.   Integrate over your bandwidth.
    
 
    Depending on system cost target, look at the ADR3425 or the ADR4525 and everything
    
 
    in between.
    
 
    Harry
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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