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LME49880 / Connect the exposed pad to V-

S.Satoshi
Guru 21685 points


Hi All,

The datasheet recommend to connect the exposed pad to V-. Please let me know the reason. Is the exposed pad connected to GND potential into the package?

Best Regards,

Sonoki / Japan Disty

  • 0
    Guru 21685 points
    Hi All,
    Please also let me know the concern if the exposed pad is not connected to V-.

    Best Regards,
    Sonoki
  • 0 in reply to S.Satoshi
    TI__Guru 62386 points
    Hello Sonoki,

    The back of the die is electrically connected to the thermal pad by conductive adhesive. Since the back of the die is at substrate potential, it must be at the most negative potential to prevent forward-biasing internal junctions.

    But since the thermal pad is exposed and floating (not part of the leadframe), the back of the die is not physically connected to V- by default. Thus, the pad must be connected to the same potential as V- to "tie down" the backside of the die.

    It is not a good idea to allow the pad to "float", as it can cause noise ingress and/or drift issues.

    This means any heatsink area will have to be at V- potential. So DO NOT ground the thermal pad (unless V- is also grounded).

    Regards,