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DAC8562: Inquiry Regarding Gain Register Issue with DAC8562SDGSR

mgtech
Prodigy 105 points
Part Number: DAC8562


Tool/software:

Dear TI Support / Technical Support Team

We are experiencing an issue while using the DAC8562SDGSR.

When setting the Gain Register, we observe that certain ICs output voltages that are twice as high as expected. This suggests a gain setting issue. Notably, when we swap the ICs, the gain error follows the specific IC, indicating it may be related to certain individual chips.

Our initialization sequence is as follows:

Software Reset

Change Power Mode

Set LDAC to Active

Disable Internal Reference

Set Gain = 1

We have tried changing the order of this sequence and adding additional commands, but the issue persists.

It appears that the gain setting might be locked or fixed in certain ICs.

Is there any method to completely reset or unlock the device so that the gain setting can be reconfigured properly?

We would appreciate any guidance or recommendations for further troubleshooting.

Best regards,

  • 0
    TI__Mastermind 42273 points

    Hello, 

    Can you share a schematic? What values are you using for the supplies and external reference? On the ICs seeing the issue, does the device respond at all when swapping between gains 1 and 2? Does the gain 2 setting see 4x the expected output? When you swap the IC are you able to adjust the gain of that device between 1 and 2? 

    Is it possible to disconnect your external reference and test the 1x and 2x gain options on one of the ICs seeing the issue? Also try disabling the internal reference and measure that is actually being disabled. 

    Can capture the write to the gain register on a device that is seeing the issue and one that is not so we can compare? 

    There isn't some setting that would permanently fix the gain. So, there's no procedure that could reset this. 

    Best,

    Katlynne Jones

  • +1 in reply to mgtech
    TI__Mastermind 42273 points

    Hello, 

    Thanks for the schematic. It looks ok to me. 

    Can you answer some of the other questions? 

    On the ICs seeing the issue, does the device respond at all when swapping between gains 1 and 2? Does the gain 2 setting see 4x the expected output? When you swap the IC are you able to adjust the gain of that device between 1 and 2? 

    Is it possible to disconnect your external reference and test the 1x and 2x gain options on one of the ICs seeing the issue? Also try disabling the internal reference and measure that is actually being disabled. 

    Can capture the write to the gain register on a device that is seeing the issue and one that is not so we can compare? 

    Best,

    Katlynne Jones

  • 0 in reply to mgtech
    TI__Mastermind 42273 points

    Hello, 

    You marked this thread as resolved so I'm not sure if you still need help. 

    What information are you trying to share in your images? Were you able to update the gain? 

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    Prodigy 105 points 
    Not processed yet

Gain value is not modified from 2...

The uploaded data says that there is no change even after doing this.
  • 0 in reply to mgtech
    TI__Mastermind 42273 points

    Hello, 

    In this case it seems like there may be some device damage here, or you are operating on some edge case of the timing requirements that allow the register write to work on some devices, but not others. 

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    Prodigy 105 points 
    I would like to contact you with more details. Can you share your email address?
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    

	            
                	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
			
		
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
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                          TI__Mastermind
                        42273 points
                      
    
                          
                   		
		
    
					
    Hello, 
    

    I've sent you a private message. You can share any additional details there. 
    

    Best,
    

    Katlynne Jones
    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    

	            
                 	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
			
		
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
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