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ADAQ23875 Recommended for New Designs
The ADAQ23875 is a precision, high speed, µModule® data acquisition solution that reduces the development cycle of a precision measurement systems by transferring...
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ADAQ23875 on Analog.com

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ADAQ23875 missing digital output



		

			

									
					    JohnZa
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Apr 2, 2023 
				
			
			
		
    

				
		
    
		    		    
		    
		    		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  ADAQ23875 
    
    		        		    		    	
			
    Hello,
    

    in the past we had done some experimentation with your ADAQ23875 eval board, all working fine.
    

    We now have implemented our own design, connecting several ADAQ23875 to a Xilinx Kintex-7 FPGA, our own VHDL code.
    

    We believe to have hooked up the ADAQ23875 exactly as outlined in the datasheet, employing single-lane mode.
    

    What we observe, for all ADAQ23875 devices connected:
    

    - on DCO we receive back the echo clock correctly
    

    - on DA we have a constant 0, irrespective of engaging TESTMODE or supplying analog input.
    

    We verified compliance to your datasheet thoroughly.
    

    We inspected the eval board documentation and found one difference to the datasheet:
    

    - eval board: pin K4 is open, NC
    

    - datasheet: pin K4 is GROUND.
    

    We appreciate any comments.
    

    

    Thanks and best regards
    

    JohnZa
    
									
			        
		
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		






					

			
    
			
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													+1
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
			                            
                        
                on Apr 3, 2023 8:47 AM
            
            
					
      
	
      

		
		
      
					
      Hi  ,
      

      Just to clarify, are you referring to the TESTPAT pin when you say TESTMODE? If I am interpreting it correctly, if you apply a HIGH (VIO) to the TESTPAT pin, you still read a constant 0 pattern instead of the 1010 0000 0111 1111 for One-lane mode? Please feel free to correct me regarding your setup.
      

       
      

      On the other hand, K4 pin is connected internally to the other ground pins of the device itself — meaning there is no problem if it is open/not connected in the evaluation board. 
      

      Few things that seem suspicious are the neighboring pins, especially the REFIN (K3) and PDB_ADC (K5), since they might be shorted to ground. 
      

        

      • If REFIN = GND: the reference buffer might have turned off, resulting to no reference voltage for the ADC core
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      • If PDB_ADC = LOW: the internal ADC core might have entered to power-down mode — meaning all circuitry (including the LVDS interface) shuts down
        • 

      

      It would be great if you could share more information regarding your configuration. Please do message in this thread if you have further queries.
      

      Thanks and regards,
      Chelsea
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
						
				
				
		
		
      
			
		
      
	
      

      

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													0
							
			
				
									
							        
			
			
			
        
            
			                            
                        
                on Apr 3, 2023 8:57 AM
            
            
												
						in reply to Chelsea
					
									
        
	
        

		
		
        
					
        Hello Chelsea,
        

        you describe perfectly well what I meant to say.
        

        Menawhile I have resolved the problem, it was due to an error within my VHDL code.
        

        I am receiving testpatterns as well as ADC samples perfectly well know.
        

        Good to know that the K4 difference eval Board/datasheet is of no relevance.
        

        Thanks a lot, very best regards
        

        JohnZa
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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													+1
							
			
				
									
							        
			
			
			
        •  Analog Employees  
        
            
			                            
                        
                on Apr 3, 2023 9:02 AM
            
            
												
						in reply to JohnZa
					
									
        
	
        

		
		
        
					
        Glad to hear that! Thanks for reaching out.
        

        Regards,
        Chelsea
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
						
						
				
				
		
		
        
			
		
        
	
        

        

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