• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 31 subscribers
  • Views 163 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.

LMT87: Direction for good thermal conductivity

Timber Lock
Prodigy 20 points
Part Number: LMT87

I want to accurately measure the temperature of a surface with the LMT87. To this end, it would be important to place the correct side of the sensor on the surface. The datasheet states: "To ensure good thermal conductivity, the backside of the LMT87 die is directly attached to the GND pin". I would want to place this "backside" on the surface. However, I am a bit confused about which side this is. Would the backside be the side of the sensor that has the smaller surface area due to the taper or the other side?

Any help is much appreciated

  • 0
    TI__Mastermind 35895 points

    All encapsulated IC packages start with a die that is attached to a leadframe. Bond wires are then attached which connect the die electrically to the leadframe's pins. Finally, the potting or encapsulation is applied to cover the die and bond wires.

    The note in the LMT87 datasheet is referring to the bottom or 'backside' of the LMT87 die being attached to this leadframe. In the case of TO-92 packages/leadframes, the GND pin is also the metal flag that the die is attached to. This means there is a strong thermal path through the GND pin to the sensor die. 

    For the LMT87 in LPG package, the leadframe is built 'face up.' The die is on top of the leadframe as shown here. However, the LP package has its leadframe built 'face down.' That means the die is underneath the pins as shown here. 

    thanks,

    ren

  • 0 in reply to Ren Schackmann
    Prodigy 20 points

    Thanks for the extensive answer, this clears it up!