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AD7147 Production
The AD7147 CapTouch™ controller is designed for use with capacitance sensors implementing functions such as buttons, scroll bars, and wheels. The sensors...
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AD7147 on Analog.com

AD7147A Obsolete
The AD7147A CapTouch™ controller is designed for use with capacitance sensors implementing functions such as buttons, scroll bars, and wheels. The sensors...
Datasheet
AD7147A on Analog.com

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How to adjust the sensitivity and calculate capacitance for AD7147

		
	
				

			

									
					    HuaWuque
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Dec 25, 2024 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Datasheet/Specs
    
    		        		            		    
    Product Number:  AD7147A  
    
    		        		    		    
    
		    		    
		    			
    
			    
      

    • I would like to adjust the sensitivity of the AD7147, for example, to increase or decrease the CDC output corresponding to 1pF. Is there a method to achieve this?
      • 

    • How can I convert the CDC output into capacitance?
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                 Datasheet/Specs
                
                                                    
                 ad7147a
                
                                                    
                 ad7147
                
                                                    
                 Integrated/Special Purpose A/D Converters
                
                                                    
                 Capacitive-to-Digital and Touch Screen Controllers
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 8, 2025 4:11 PM
            
            
						
			            		
      
		
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      Hi HuaWuque,
      

      It is not possible to change the sensitivity, the input range is fixed at +/- 8pF, the CDC is 16-bit resolution so each count has a weight of 16pF/65536 = 244 aF.
      

      If an offset capacitance is configured this should be added to the total capacitance value at 0.32pF per count
      

      Regards,
      

      Maurice.
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 8, 2025 4:11 PM
            
            
						
			            		
      
		
										0
					
	
      

		
		
      
		
      
                                
                                                            
      
					
      Hi HuaWuque,
      

      It is not possible to change the sensitivity, the input range is fixed at +/- 8pF, the CDC is 16-bit resolution so each count has a weight of 16pF/65536 = 244 aF.
      

      If an offset capacitance is configured this should be added to the total capacitance value at 0.32pF per count
      

      Regards,
      

      Maurice.
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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