Products Mentioned

AD7683 Production
The AD7683 is a 16-bit, charge redistribution, successive approximation, PulSAR® analog-to-digital converter (ADC) that operates from a single power supply...
Datasheet
AD7683 on Analog.com

ADR435 Production
The ADR430/ADR431/ADR433/ADR434/ADR435 series is a family of XFET® voltage references featuring low noise, high accuracy, and low temperature drift performance...
Datasheet
ADR435 on Analog.com

Thread Details

  • State Verified Answer
  • Replies 2 replies
  • Subscribers 76 subscribers
  • Views 4171 views
  • Users 0 members are here
Options
 
Related Content

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
Use of TL431 for voltage reference of AD7683

		
	
				

			

									
					    gigarashi
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 12, 2017 
				
			
			
		
    
		
		                    	    
    
        	    
    Thread Summary
    
                The user inquired about using the TL431 voltage reference for a 5V Vref input in the AD7683 ADC, questioning its noise performance. The TL431 is not suitable for a 16-bit ADC due to its 50 ppm/°C tempco and higher noise. The final answer suggests considering the ADR3425 or ADR4525 for better performance, and to integrate the noise over the system bandwidth as shown in the TI datasheet's noise curve (Fig. 7).
                        	    
    
                
                     AI Generated Content
                
    	    
    
             
				
        		
    
		    
		    		    
		    			
    
			    
    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,
    
			
    
			
									
		                             
                        

    
    
                                            
                 adr435
                
                                                    
                 Single Channel A/D Converters
                
                                                    
                 Series Voltage References
                
                                                    
                 ad7683
                
                                                    
                 voltage references
                
                                        
                                            
                
                
                                
                    Show More
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							FormerMember
					
      
		
      
		    
		    		    
			
				
									FormerMember
							        
			
			
			
    
            
						
                            
            
            				
            
                on Jan 12, 2017 7:28 PM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    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
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    


	

  • 
	
    



	
			
		
	



    
	
    
		
    
							
					
    
		
    
		    
		    		    
			
				
									
							        
			
			
			
      
            
						
                            
            
            				
            
                on Aug 2, 2018 11:41 AM
            
            
						
			            		
      
		
										0
					
	
      

		
		
      
		
      
                                
                                                            
      
					
      This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

      Thank you,
      EZ Admin
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

      •