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LM57: LM57 Lower operating temperature and Thermal constant

Malli R
Prodigy 30 points
Part Number: LM57

Hi,

We are planning to use LM57 in one our application.

The application works from -55 deg C. LM57 will act as  thermostatic switch in our application.

 

Tover threshold = -35 degC.

 

when temperature < -35 degC , Tover#(Open drain) will not be driven (default HIGH) which turns ON a heater(basically resister n/w).

When temperature > -35degC Tover# will be driven LOW and Turns OFF the heater.

 

 The operating temperature of LM57 is below.

 

Can the LM57 behavior can be estimated for -50 °C to -55 °C temperature range?

---> When ambient temperature < -35 degC ( -55 degC to -35 degC ) Tover#(active LOW) should be driven LOW. Whether this can be achieved.

 

 

 

  • 0
    Prodigy 30 points
    The first post has some problems. So i am posting it again.


    We are planning to use LM57 in one our application.

    The application works from -55 deg C. LM57 will act as thermostatic switch in our application.


    Tover threshold = -35 degC.


    when temperature < -35 degC , Tover#(Open drain) will not be driven (default HIGH) which turns ON a heater(basically resister n/w).

    When temperature > -35degC Tover# will be driven LOW and Turns OFF the heater.



    The operating temperature of LM57 is -50 degC to 150 degC.

    Can the LM57 behavior can be estimated for -50 °C to -55 °C temperature range?

    ---> When ambient temperature < -35 degC ( -55 degC to -35 degC ) Tover#(active LOW) should not be driven LOW. Whether this can be achieved
  • 0 in reply to Malli R
    TI__Expert 6475 points
    Let me have a look.

    -Kelvin
  • 0 in reply to Kelvin Le THS
    Prodigy 30 points

    Hi Kelvin,

    Few have few decisions to be made from this. Do you have any update on this.

  • 0 in reply to Malli R
    TI__Expert 6475 points

    Malli,

    Unfortunately, -55C is outside of the recommended operating range so any estimation can not be guaranteed.  The problem is some parts may work outside of -50C but when you have a large sample size like in production you might run into issues since the operating range is in uncharted territory.

    -Kelvin