• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 64 subscribers
  • Views 316 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.

LMZM33603: Datasheet Grounding Recommendation

Grace Andersen
Prodigy 10 points
Part Number: LMZM33603

In the datasheet for this component, there is an analog ground and a power ground. The pin description for AGND says to not connect AGND and PGND, and that the connection is made internal to the device. Are there potential problems from connecting them? Is it possible to just use one ground for the device?

  • 0
    TI__Mastermind 25590 points

    Grace,

    Yes, do not connect AGND to PGND on the layout. AGND for this device needs to be quiet. PGND has noise from the power stage so separating these pins (in this device) is advised. See the layout guidelines for a typical layout. Connecting them may introduce noise which can affect regulation and stability. Using just one GND would force the noise-sensitive circuitry to effectively use PGND for grounding which would introduce noise from the power stage into the noise-sensitive circuitry.

    This is not the case for all devices so it's important to check the datasheet.

    -Sam

  • 0 in reply to Samuel Jaffe
    Intellectual 920 points

    Hi Sam,

    Should AGND be considered an island that is isolated to the LMZM33603 and only used to connect to the Rt resistor and feedback resistors? Then PGND can be connected (same net) to circuit GND for the rest of the design, correct?

    Thanks,

    Jim