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AD5940 Recommended for New Designs
The AD5940 and AD5941 are high precision, low power analog front ends (AFEs) designed for portable applications that require high precision, electrochemical...
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AD5940 on Analog.com

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Convert ADC Code to current in Amperometric measurement

		
	
				

			

									
					    ad5940Freshman
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Feb 14, 2024 
				
			
			
		

		
		                    	    

        	    
Thread Summary

                The user inquires about the adjustability of ADCPgaGain during a single measurement and the determination of RtiaCalValue.Magnitude in the AD5940 amperometric code. The final answer confirms that ADCPgaGain can be updated in the AppAMPRegModify() function and explains that RtiaCalValue.Magnitude is the calibrated value of the internal RTIA resistor, set by the AppAMPRtiaCal() function using the AppAMPCfg.LptiaRtiaSel parameter.
                        	    

                
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Category: Software

    		        		            		    
Product Number:  AD5940 

    		        		        		        
Software Version: Keil5

    		    		    

		    		    
		    			

			    
Hi,


I am looking into the code of amperometric for AD5940 and have two questions. Is ADCPgaGain adjustable during a single measurement? What I found the most confusing is the calculation of current. How is RtiaCalValue.Magnitude determined? I did not find it in the code. Attached is the relevant code. I really appreciate your answers.


Thanks,


Peter


 

			

			
									
		                             
                        

    

                                            
                 software
                
                                                    
                 amperometric
                
                                                    
                 sensors
                
                                                    
                 Sensors and MEMS
                
                                                    
                 KEIL5
                
                                        
                                            
                
                
                                        
                                            
                
                
                                
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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Feb 15, 2024 1:06 AM
            
            
						
			            		
    
		
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    Hi,
    

    1) After each measurement, you can change ADC PGA gain by updating it inside AppAMPRegModify() function by including below lines in it:
    

     DSPCfg_Type dsp_cfg;
    

    dsp_cfg.ADCBaseCfg.ADCPga = new PGA gain value;
    

    AD5940_DSPCfgS(&dsp_cfg);
    

    

    

    2) RtiaCalValue.Magnitude is the magnitude of calibrated value of internal RTIA resistor ( feedback resistor of LPTIA). 
    

    This calibration is done by AppAMPRtiaCal() function.
    

     AppAMPRtiaCal() function needs RTIA value input from user which is set by AppAMPCfg.LptiaRtiaSel.
    

    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
						
						
				
				
		
		
    
			
		
    
	
    

    

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