Thread Details

  • State Not Answered
  • Replies 1 reply
  • Subscribers 32 subscribers
  • Views 336 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
AD5424: How to calculator  R1 and R2 value?

		
	
				

			

									
					    Vanper
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jun 16, 2021 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    Hi,
    

    I designed a application use AD5424 and Op Amps UA741CDT with Vref =+5V, C1=1pF in below.
    

    I want the voltage of the Vout from 0V to -5V. How to calculator value R1 and R2 ? 
    

    

    P/s: I try to use R2 and R1=0 ohm but the Vout =1.9V and the Vout don't change when i change the data inputs?
    

     
    
			
    
			
									
		                             
                        

    
    
                                            
                 Precision D/A Converters
                
                                                    
                 Multiplying Current Output D/A Converters
                
                                                    
                 ad5424
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
		    
		    		    
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jun 18, 2021 5:24 AM
            
            
						
			            		
      
		
										0
					
	
      

		
		
      
		
      
                                
                                                            
      
					
      Hi, 
      

      In you case, with a Vref of -5V, there's no need to put R1 or R2, or just set them to 0 as you did. Your Vout range should be 0 to -Vref. If you followed the circuit, everything should be fine for your DAC. Next thing you could check is your data input. Make sure you're following the timings provided in the datasheet Figure 2 and Table 2. 
      

      What you can check is the connection of your opamp. Make sure you connect the IOUT1 to the -in and the IOUT2 to +in/gnd. Also check that you are supplying enough on you amplifier. You might need lower than -5V depending on your opamps spec. you could try -7V or lower. 
      

      Best regards,
      

      Ian
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

      •