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TMP708: How to Test the TMP708 functionallity at 20C - with Rset set to 100C trip point?

Bond - James Bond
Expert 4910 points
Part Number: TMP708

Hello Temp Sensor experts

How to Test the TMP708 functionality at 20C - with Rset set to 100C trip point ?..

Customer needs to in the production test the functionality of the TMP708 at Ta= 20C - while having the Rset mounted and set to trip at 100C?

This si needed to satisfy the safety approval in certain products..

The SET pin must be with in gnd and Vdd so applying an extern voltage to emulate lower trip temp would be ok ?  or?

Any other advise / recommendations on  how to test the functionality in production line?

  • 0
    TI__Mastermind 35855 points
    Hi James,

    Thank you for your question. A TI representative will get back to you tomorrow, as today is a holiday.

    Thanks for your understanding,
    Ren
  • 0
    TI__Genius 12780 points

    Hi James Bond,

    The customer wants to ensure that the TMP708 does not trip while the testing temperature is 20C and the trip temperature is 100C? I'm not sure I understand what is actually being tested.

    There is a current source at the SET pin that creates a voltage when a resistor is applied between SET and GND, so I would suggest using the resistor here.

    Best Regards,

    Dan

  • 0 in reply to dBrock
    TI__Expert 4910 points

    Hi Dan,

    Other way around. Trip point  is set to 100C but on the production line the Ta temperature is say 20C.. How to verify the TMP708 is functional at 20C TA when set point is 100C??

    I assume we can force the SET pin with an external voltage??  or even better superimpose current from an external current source?

  • 0 in reply to Bond - James Bond
    TI__Expert 6475 points
    James,

    I will ask our designer to get some feedback.

    -Kelvin
  • 0 in reply to Kelvin Le THS
    TI__Expert 6475 points
    James,

    The SET pin can be driven with an external voltage as long as the voltage does not exceed VCC. You can also connect a resistor to the SET pin and add an external current source to raise the voltage until the pin trips.

    If the customer is trying to trip the TMP708 when the ambient temperature is 20C to make it think that it is at 100C, then the customer can raise the voltage on the SET pin at 20C until the output pin /OT goes from high to low.

    -Kelvin