• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 31 subscribers
  • Views 280 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMT01: Problems of LMT01 Temperature Sensor

ilhan can adibelli
Prodigy 10 points
Part Number: LMT01

Hello E2E,

We are using your product with part number LMT01DQXT in our project. However, we run into some problems. We use 22k resistor for the sensor. Usually There is no problem with temperature measurement for a while. And we measure a voltage of 0.8V on the resistor. But sometimes there is no pulse from the sensor and the value 1 is constantly coming. On the resistor voltage rises to 1.8V. Sometimes we do not encounter any problems. What could be the reason for the indecision here?
Thanks, 
Sincerely.

  • +1
    TI__Mastermind 41135 points

    Can you show a schematic including the supply voltage? 

    I have to assume your circuit looks like this, with the 22kohm connected to ground below the LMT01. 22kohm is larger than the examples in our datasheet and will impact the logic levels that need to be detected by the MCU. Also note that there must be a minimum of 2V across the LMT01 while 134uA passes through the resistor, otherwise LMT01 will not operate correctly. You would need a 5V supply.

    The 0.8V that you report is the correct logic low output for a 22kohm resistor. 34uA*22kOhm. The logic high output should be 2.75V. 125uA*22kOhm. If your supply is 3.3V, the LMT01 will brown-out due to low voltage before it can reach 2.75V output.

    thanks,

    ren

  • 0 in reply to Ren Schackmann
    Prodigy 10 points

    First off all thanks Ren,
    We can think of the schmeatic as similar, but we used fpga. We can't feed with 5V our custom board. And we couldn't get any measurement information with the 6.81k resistor.

    We have now resolved the situtation in a different way. I would like to share it for information.

    When the error condition I mentioned above comes, I send 3.3V to the Vn pin via fpga. As a result of this process, the sensor is reset and starts working again.
    thanks,
    Can

    

    
			
    

		
		
		
		
	
    
	
    
		
    
			
		
    
	
    

	            
                	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
			
		
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
    •