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ADP2442 Recommended for New Designs
The ADP2441 / ADP2442 is a constant frequency, current mode control, synchronous, step-down, dc-to-dc regulator that is capable of driving loads of up...
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ADP2442 on Analog.com

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ADP2442 shutdown output after some seconds



		

			

									
					    staticboards
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jan 30, 2018 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi!
    
 
    We are evaluating the ADP2442 ic. Our prototype is a basic dc dc converter, from 24V to 5V
    
 
    This is the schematic (basically a copy&paste of the reference design):
    
 
    
 
    If we connect the pin 6 (SYNC/MODE) to gnd (pulse skip mode), the circuit seems to work. We have 5V and we can supply current for a test load.
    
 
    But if we use the fixed mode (pin 6 to vcc), the circuit works for a couple of seconds, and then, it shutdowns. We were looking for something strange, but at first, we dont see anything.
    
 
    any idea or suggestion?
    
 
    Thank you very much!!!
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Internal Power Switch Buck Regulators
                
                                                    
                 adp2442
                
                                                    
                 power
                
                                                    
                 dcdc
                
                                                    
                 Step-Down (Buck) Regulators
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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                on Feb 5, 2018 9:46 AM
            
            
					
        
	
        

		
		
        
					
        Thank you for your reply!!
        
 
        AGND and PNGD are connected under the ic. You can see it on the schematics, on the pin 13. I followed the layout guidelines for this. Do you see anything strange here then?
        
 
        We damaged the chip doing tests (short playing with the multimeter pin) and we are waiting for a new one. I will post more infor about this. But I remember using a led to drive some current, with the same result.
        
 
        For sure, with no load, the ADP2442  shutdown after 3 or 4 seconds in fixed mode.
        
 
        Also, in skip mode and fixed mode, the LED on the PGOOD pin does not turn on :/ that is the most disturbing issue here.
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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													0
							
			
				
									
							        
			
			
			
          
            
						
                            
            
            				
            
                on Feb 5, 2018 9:46 AM
            
            
					
          
	
          

		
		
          
					
          Thank you for your reply!!
          
 
          AGND and PNGD are connected under the ic. You can see it on the schematics, on the pin 13. I followed the layout guidelines for this. Do you see anything strange here then?
          
 
          We damaged the chip doing tests (short playing with the multimeter pin) and we are waiting for a new one. I will post more infor about this. But I remember using a led to drive some current, with the same result.
          
 
          For sure, with no load, the ADP2442  shutdown after 3 or 4 seconds in fixed mode.
          
 
          Also, in skip mode and fixed mode, the LED on the PGOOD pin does not turn on :/ that is the most disturbing issue here.
          
			
          

		
			
	      

		
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

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