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AD8672 Production
The AD8671/AD8672/AD8674 are very high precision amplifiers featuring very low noise, very low offset voltage and drift, low input bias current, 10 MHz...
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AD8672 on Analog.com

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AD8672 working temperature

		
	
				

			

									
					    Cain
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Dec 23, 2024 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
    
		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  AD8672  
    
    		        		    		    
    
		    		    
		    			
    
			    
    Hi, 
    

    We’re using an AD8672 as both a gain/shift buffer and an ADC input driver, powered by ±12 V rails.
    

    In a “standby” condition, the AD8672 package temperature measures around 40+ °C—roughly 10 °C higher than other op amps (e.g., OPx177) on the same board under similar conditions.
    

    To investigate, we tried:
    

      

    1. Letting the input (Vin) float or tying Vin to ground.
      2. 

    2. Removing R10 and R16 to float the output.
      3. 

    

    In both cases, the device temperature remains around 40+ °C. We’ve attached our schematic and a temperature diagram for reference.
    

    Is this temperature rise typical for an AD8672 operating at ±12 V? Are there any design considerations or power dissipation factors we should check to confirm this is within normal operating limits?
    

    Thanks for your assistance!
    

     
    

     
    
			
    
			
									
		                             
                        

    
    
                                            
                 Operational Amplifiers (Op Amps)
                
                                                    
                 hardware
                
                                                    
                 ad8672
                
                                                    
                 Precision Op Amps (Vos ≤1mV & TCVos ≤2uV/C)
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jan 6, 2025 12:41 AM
            
            
						
			            		
      
		
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      Hello Cain,
      

      Does this happen on other boards too? Have you tried another AD8672 part to check if it is not part specific?

      

      Thanks and Best Regards,
      Kenneth
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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                on Jan 6, 2025 9:13 PM
            
            
												
						in reply to Kenneth11
					
										
			            		
        
		
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        Hi Kenneth,
        

        Yes, this happens on all our prototype boards, not just a single unit or a single AD8672 part.
        

        Our AD8672’s input (Vin) is driven by a MUX, so initially, we suspected that frequent switching of the MUX might be adding extra power consumption. However, even when we keep the MUX on a fixed channel or disconnect the output, the AD8672 still settles at around 40°C.
        

        We’re mainly curious if this behavior is considered “normal” for the AD8672 operating on ±12V rails. Any insight or guidance would be greatly appreciated.
        

        Kind regards,
        

        Cain
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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        •  Analog Employees  
        
            
						
                            
            
            				
            
                on Apr 14, 2025 3:10 AM
            
            
												
						in reply to Cain
					
										
			            		
        
		
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        Hello  ,
        

        Sorry for the late reply. I checked this query again and upon looking at the DS, it seems that what you are seeing is correct for AD8672.
        On page 11 on the DS at Power Dissipation section, it says junction temperature is expected to be 42C if ambient temp is 30C on AD8671 single MSOP package.
        

         
        

        Since you are using AD8672, power dissipation is twice as that of single package, so you will get around 23.8C rise above ambient temperature.
        So let's say your ambient temp is 23C, you'll expect 46.8C junction temp when both opamps are powered up (rise in temp is excluding load currents on your output if your op amp is connected to a load).
        

        

        Thanks and Best Regards,
        Kenneth
        
			
        

		
			
	      

		
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

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