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ADN8835 Recommended for New Designs
The ADN8835 is a monolithic TEC controller with an integrated TEC controller. It has a linear power stage, a pulse-width modulation (PWM) power stage,...
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ADN8835 on Analog.com

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ADN8835 voltages of TEMPSET vs temperature - how to calibrate

		
	
				

			

									
					    tk_cybel
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 7, 2021 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    It is perhaps an unlearned question.... no, it definitely is an unlearned question......I'm scratching my codie head  :)
    

    If I use a NTC thermistor of 10k ohms as the sensor - how can I set the temperature in terms of voltage at the TEMPSET input, and read the temperature from the TEMPOUT output?  In other words, I think the question is what is the gain I can expect from the thermistor input to the TEMPOUT output?
    

    I am starting with the ADN8835-EVALZ evaluation board.  
    

    Thanks in advance for your valuable time to answer.
    
			
    
			
									    
    
			        
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[edited by: tk_cybel at 11:40 AM (GMT -5) on 7 Nov 2021]
				
    
						
		                             
                        

    
    
                                            
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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Nov 7, 2021 10:47 PM
            
            
						
			            		
      
		
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      Hi,
      

      Moving this thread to Power By Linear. Someone should be able to answer your query. 
      


      Cheers,
      

      Ivan
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
				
				
				
		
		
      
			
		
      
	
      

      

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Nov 8, 2021 4:46 AM
            
            
						
			            		
      
		
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      Hi ,
      

      

      Thanks for reaching out.
      

      As for your question, it will be depending on your thermistor amplifier network component values. 
      First, you need to define the temperature you are going to maintain and the boundaries.
      

      The lower temp boundary will be TLOW, the target temp as TMID and the higher boundary as THIGH.
      The output of the thermistor network amplifier should swing between ~0.3V (ideally 0V) and 2.2V (ideally 2.5V).
      The curve in the datasheet figure 34 is an example with the TMID = 25degC +/- 40degC as limit.
      The step by step process in computing the values in order to obtain the curve is in the thermistor amplifier setup section of the datasheet.

      

      Now, the corresponding OUT1 voltage of the temperature set in the thermistor amplifier network will be the TEMPSET value.
      hope this helps. 
      


      Regards,
      Noel
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
				
				
				
		
		
      
			
		
      
	
      

      

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                on Nov 8, 2021 5:34 AM
            
            
												
						in reply to ntenorio
					
										
			            		
        
		
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        It is very helpful indeed.  I did not know the useful ranges of the OUT1 amplifier, and it did not occur to me that Figure 34 was telling me.   Knowing this and the other information you provided, I'm able to see the procedure more clearly.
        

        I have more digging to do.  Thank you for taking your time to reply to my question.  I'm going to see where I go with this.
        

        

        

        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
				
				
				
		
		
        
			
		
        
	
        

        

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