• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 33 subscribers
  • Views 161 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

THVD1439: Query about the Surge Ground Pin connection on Sensor Node

Neet
Intellectual 612 points
Part Number: THVD1439

Tool/software:

Hello E2E Community,

We are considering the use of THVD1439 Surge Protected TRx for our use case, and are slightly confused about the grounding when using this Surge Protected TRx on our board.

Traditionally we have kept the Ground pins of TVS Diodes separate from the digital ground of the MCU, but in this case the Datasheet explicitly outlines to connect the TRx ground to the MCU ground.

Want to confirm once more - is this acceptable practice in case of surge events? Does the 70V & 100A current at the bus pins mean this is how much the ground might bounce when shunting the surge from TVS to the ground pin?

Kindly guide.

  • 0
    TI__Guru 73971 points

    Hi Neet,

    Neet said:

    We are considering the use of THVD1439 Surge Protected TRx for our use case, and are slightly confused about the grounding when using this Surge Protected TRx on our board.

    Traditionally we have kept the Ground pins of TVS Diodes separate from the digital ground of the MCU, but in this case the Datasheet explicitly outlines to connect the TRx ground to the MCU ground.

    Want to confirm once more - is this acceptable practice in case of surge events?

    No, I don't think you need to follow the reference schematic on the example in the datasheet. I believe when this was generated they wanted to simplify the drawing by making the grounds the same. If you have a separate analog ground then you can use that instead.

    Neet said:
    Does the 70V & 100A current at the bus pins mean this is how much the ground might bounce when shunting the surge from TVS to the ground pin?

    No, I believe this is in reference to the clamping voltage when the TVS turns on. For example, if the TVS sinks 50A of current the TVS's voltage will be 50V during the transient event.

    -Bobby