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ADPD188GG Recommended for New Designs
The ADPD188GG is a complete photometric system designed to measure optical signals from ambient light and from synchronous reflected light emitting diode...
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ADPD188GG on Analog.com

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Maximum Average Current of Internal LEDs ADPD188



		

			

									
					    El_Dirk
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 23, 2021 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    Hi,
    

    what is the maximum (average) current rating for the internal green LEDs in the chip? When using normal mode with 2µs pulse width and 19µs period it can not exceed 40mA even with 370mA peak current. But in float mode (synchronous LED measurement) with 31µs pulse width the on/off-ratio of the LED could be much higher. Where is the limit (we have very weak signals) - in 40mA average or higher?
    

    Regards
    Dirk
    
										

    
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[edited by: lallison at 4:50 PM (GMT -5) on 9 Feb 2022]
				
    
					
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		
	
    















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
			                            
                        
                on Dec 7, 2021 1:42 AM
            
            
					
      
	
      

		
		
      
					
      Hi Dirk,
      

      The peak CW (always on current) of the LED by the vendor is 30mA. With 2µs pulse width, the average current is below 30mA even with 370mA peak current due to the small duty cycle of the pulse.
      

      Float mode allows wider pulse hence a higher average current can be achieved with relatively high peak current.
      

      Regards,
      

      Glen B.
      

      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
			                            
                        
                on Dec 7, 2021 1:42 AM
            
            
					
      
	
      

		
		
      
					
      Hi Dirk,
      

      The peak CW (always on current) of the LED by the vendor is 30mA. With 2µs pulse width, the average current is below 30mA even with 370mA peak current due to the small duty cycle of the pulse.
      

      Float mode allows wider pulse hence a higher average current can be achieved with relatively high peak current.
      

      Regards,
      

      Glen B.
      

      
			
      

		
		
		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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