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Original question:

TCA9539: TCA9539RTWR THERMAL PAD

TCA9539: exposed pad wiring?

Stefan Lintner
Expert 5185 points
Part Number: TCA9539

Hi Team,

What is the recommended wiring of the exposed center pad?

Should it be connected to GND?

BR,
Stefan

  • 0
    TI__Mastermind 47998 points

    Hi Stefan,

    There is nothing indicating in the datasheet that the "exposed center pad" is electrically connected to any of the external pins. This pad is for a more stable solder connection, but also serves as a thermal relief mechanism to pull heat away from the IC. Most will say to connect this center pad to GND due to the GND plane in most PCB's being a very large piece of metal which is good for thermal conduction. This exposed pad can either be connected to a GND plane or a VCC plane, whichever the customer prefers. 

    Main idea: connect the pad to a large piece of metal on the PCB. 

    Regards,

    Tyler

  • 0
    Guru 317260 points

    The pad is glued to the substrate, which typically is at GND potential. The glue might be electrically conductive. So the pad, if not left floating, should not be connected to any other voltage than GND. See [FAQ] Where do I connect the thermal pad of the logic QFN devices?