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The connection of Exposed Thermal Die Pad on INA333's Underside.

Other Parts Discussed in Thread: INA333, OPA454

Hello,

My name is SANG RAE LEE worked for PANAXTOS in Korea.

We are developing EEG system including INA333 which have thermal die pad on underside.

What is your recommended connection for thermal pad?

Ground(0V) or Floating ?

We have used bi-supply(AVDD : +2.5V, AVSS : -2.5V, REF : +1.2V).

Thank you.

Bye.

  • Hello Sang Lee,

    Please see a previous INA333 E2E post:

    Thus, AVSS : -2.5V.

    Regards, Thomas

    PA - Linear Applications Engineering

  • Hello, Thomas.

    Thank you for your answer about INA333's thermal pad connection.

    What is particular reason about connecting thermal pad to AVSS(-2.5V) instead  of Ground(0V)?

    In general,we have known that thermal pad is connected  to ground  or floating.

    We will wait your answer.

    Thank you.

    Bye.

  • Hello Sang Rae,

    The INA333 die uses the common junction isolation method to keep the transistors and other elements of the integrated circuit electrically isolated from each other. The substrate of the INA333 die is electrically connected to the leadframe flag via conductive epoxy. That  PowerPad is also connected to pin 4, (V-). Therefore, the PowerPad must be connected to the V- potential.

    If you would like a more visual example, see the OPA454 datasheet, Layout Section 12.1, sections 12.1.1 and 12.1.2, especially Figure 84. Once you have a look at those sections of that datasheet the PowerPad assembly should be more clear.

    Regards, Thomas

    PA - Linear Applications Engineering