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AD9577 Recommended for New Designs
The AD9577 provides a multioutput clock generator function, along with two on-chip phase-locked loop cores, PLL1 and PLL2, optimized for network clocking...
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AD9577 on Analog.com

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AD9577 documentation question regarding PDRefOut default value

		
	
				

			

									
					    jaynoc
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Oct 29, 2025 
				
			
			
		

		
		                    	    

        	    
Thread Summary

                The user asked if the REFOUT power-down setting should be 'set to 1' to disable the output, given the default value is 0 and REFOUT is enabled by default. The support engineer confirmed that setting PDRefOut to Logic 1 in Register DR2[0] (0x3B) powers down REFOUT, and the datasheet will be updated accordingly.
                        	    

                
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Category: Datasheet/Specs

    		        		            		    
Product Number:  AD9577  

    		        		    		    

		    		    
		    			

			    
The datasheet says the REFOUT "can be optionally powered down by setting Register DR2[0], PDRefOut to Logic 0."  Should this say 'set to 1' to disable the output?  Table 31 says the default value of PDRefOut is 0, and I assume REFOUT is enabled by default.

			

			
									
		                             
                        

    

                                            
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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Oct 30, 2025 6:53 AM
            
            
						
			            		
    
		
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    Hi,
    

    

    I looked in the eval software. I loaded an old stp file I had. This file had the register 0x3B set to 0x0. The eval software shows REFOUT as being on.
    

    I then clicked the option "Reset to Defaults" and REFOUT stayed on. This showed me the default value of that bit 0 in register 0x3B is 0.
    

    Then I changed in the eval software REFOUT to be Off. The software then created a stp file with the register 0x3B having the value 0x1.
    

    So I've made a note in the data sheet that the phrase you point to should be changed as follows: "This buffer can be optionally powered down by setting Register DR2[0], PDRefOut to Logic 1."
    

    Petre
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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