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LM71 Pad

LAUNCHXL-F28377S user
Prodigy 165 points
Other Parts Discussed in Thread: LM71

Hi,

1. I want to measure the temperature of LEDs. I want to place the LM71 next to the LED and want to connect the Pad of the LED with the PAD of the LM71. The PAD of the LED is connected to 5V. Now I want to know if this is possible? I cant find any informations in the Datasheet of the LM71 if there is an electrical connection between the Pad and the die.

2. Also I dont undestand what means no pull back in this sentence: the 6-pin WSON (no pull back) package.

3. Also I dont understand the Soldering Information. How should I get a chip with a pad on a board with these specs?

  • 0
    TI__Mastermind 31980 points
    Hi,

    Let me check the database, and I get back to you.

    Aaron
  • 0 in reply to Aaron Heng
    TI__Mastermind 31980 points

    Hi,

    1. I reviewed the leadframe for the LM71. The DAP of the LM71 is connected to the substrate of the die; therefore, you cannot connect 5V of the LED's Pad. This will create a short to 5V to GND.

    2. I drew a picture for you, and hope this will help you visualize the two difference. Basically, the "No Pull Back" term is represented the pads of the LM71 align with the edge of the mold compound. This will allow people to inspect if there is any cold solder joint.

    3. The value specified in the soldering information is abs max, but I would suggest to use the soldering profile from this link below.

    Hope this helps! Let me know if you have further question.

    Aaron

  • 0
    TI__Expert 4905 points
    Hi,

    The pad is connected to the back side of the die and should be grounded or left floating. Unfortunately you cannot connect it to 5V.

    No- pullback means there is a very small exposure of the pins on the side of the package instead of them being completely covere with mold compound.

    I will send you a link to an app note on a bit that describes the soldering profile better.

    Take care,