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LTC4266 Recommended for New Designs
The LTC4266 is a quad PSE controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet systems. External power...
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LTC4266 on Analog.com

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LTC4266 FETBAD event

		
	
				

			

									
					    HankKuo1982
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Apr 26, 2023 
				
			
			
		
    
		
		                    	    
    
        	    
    Thread Summary
    
                The user inquired about methods to clear the fetbad bit in the LTC4266 software interface. The support engineer clarified that the RESET pin, rstall bit, and rsrt1-4 bits can all be used to clear the fetbad bit, but the RESET pin and rstall bit reset the entire chip, while rsrt1-4 bits reset only the respective port. Setting the rst1-4 bit is identical to setting the off1-4 bit, and the fetbad bit will reset if the underlying issue is resolved.
                        	    
    
                
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    Category: Software
    
    		        		            		    
    Product Number:  LTC4266 
    
    		        		    		    
    
		    		    
		    			
    
			    
    Hi Sir 
    

    in LTC4266 software interface document it said "The fetbad bit can only be cleared by resetting the port" , 
    is the "reset" action triggered by RESET pin, register 1Ah[4] = rstall or register 1Ah[3:0] = rst1234 ?  or all three method are workable?
    the function description for rstall and rstn looks a bit different, 
    rstall is identical to RESET pin low, but rstn is identical to pwepb off bit, 
    Could you please explain the difference between the two clearly?
    
			
    
			
									
		                             
                        

    
    
                                            
                 LTC4266
                
                                                    
                 PoE Power Sourcing Equipment (PSE)
                
                                                    
                 software
                
                                                    
                 Power-over-Ethernet (PoE) Interface Controllers
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                                                    
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on May 5, 2023 8:02 PM
            
            
						
			            		
      
		
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      The RESET pin and the rstall bit will reset the whole chip to the AUTO pin reset state; this will affect all four ports.  The rsrt1-4 bit will reset only that respective port and not affect the other ports. As stated in the LTC4266 software interface datasheet, setting the rst1-4 bit is identical to setting the off1-4 bit.
      

       
      

       
      

      All methods will work to clear the fetbad bit.  However, if the cause of the fetbad is still present after one of these reset methods, the fetbad will return to set.
      

       
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
				
						
				
				
				
		
		
      
			
		
      
	
      

      

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