• State Verified Answer
  • Replies 4 replies
  • Subscribers 32 subscribers
  • Views 801 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    









		











	
	
			
	
			
		
	
	
		

		
AD5672R not setting its output to default value while in RESET



		

			

									
						MPuech657
					
							

			
				
									
											
							 		
		        	            							
			
			    	
			                    
                
				                on Jan 9, 2020 
				
			
			
		


				
		

		    		    
		    
		    	
			
Hi,


I am not able to use the RESET pin to set the DAC outputs to default values before I program the DAC.




Here is what I do :


- RSTSEL is set to VLOGIC, because I want a default output voltage of 2.5V


- t0 : DAC V_LOGIC is supplied with 3.3V ; RESET is hold high


- t1 : DAC VDD is supplied with 5V


- t2 : RESET is set low for 10ms, and back high. I did this to be sure the DAC outputs were at a safe value (2.5V) before I program the DAC. But it does not work: the DAC outputs stay at 0V during the 10ms RESET.


- t3 : I program the DAC to output a voltage of 3.3V. It works properly




Am I doing something wrong? Why don't I have 2.5V at the output of my DAC during RESET? 




One funny thing iI noticed is that if I keep the RESET pin high all the time, the DAC is setting its output to 2.5V after is it powered up, which is what I want. But it is doing the opposite of what is said in the datasheet... I need this to be clarified.




Thank you,


Maxime Puech

								


				
				
		

			
						
									
									
						
						
			
			
			
			
		


					

			





	














	

	

					



			








	
	
	
	



Parents
	
    
	

  • 
	
    



	
			
		
	



    
	
    
		
    
							
					
    
		
    
			
													+1
							
			
				
									
							        
            
                                                                                                        
      
                            
    • 
                                 Analog Employees 
                                
                            
      • 
                        
     
                                                           			
			                            
                        
                on Jan 10, 2020 7:32 AM
            
            
					
    
	
    

		
		
    
					
    Hi Maxime,
    

    The output will only go to the determined reset value as dictated by the RSTSEL value 'after' RESET pin is released or pulled back to logic high.
    

    As long as RESET pin is low, the output is 0V.
    

    This is the expected behavior of the part, is this what you're observing?
    

    

    Cheers,
    

    Ivan
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

    • 

	

  • 
	
    



	
		
	
	



    
	
    
		
    
							
					
    
		
    
			
													0
							
			
				
									
							        
            
                                    			
			                            
                        
                on Jan 10, 2020 1:43 PM
            
            
												
						in reply to isantos
					
									
    
	
    

		
		
    
					
    Hi Ivan,
    

    Thank you for your answer. Yes this is the behavior I am onserving; the part behaves as expected. But I think the datasheet is not clear enough about this.
    

    It leads me to another question. What happens on the DAC outputs if I never reset the DAC by keeping the RESET pin high all the time? Does the DAC have a power on reset ? Will the DAC go to the determined reset value as dictated by the RSTSEL pin by itlsef?
    

    Thanks,
    

    Maxime
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

    • 

	

  • 
	
    



	
		
	
	



    
	
    
		
    
							
					
    
		
    
			
													0
							
			
				
									
							        
            
                                                                                                        
      
                            
    • 
                                 Analog Employees 
                                
                            
      • 
                        
     
                                                           			
			                            
                        
                on Jan 14, 2020 1:34 AM
            
            
												
						in reply to MPuech657
					
									
    
	
    

		
		
    
					
    Hi Maxime,
    

    Sorry I did not understand your question. But the part will still reset of you cycle the power or supply of the DAC due to the POR block. And yes, the output state after reset will be dictated by RSTSEL pin.
    

    One more way to reset is to use the SOFTWARE RESET command.
    

     
    

    Cheers,
    

    Ivan
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

    • 

	




Reply



Children