• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 83 subscribers
  • Views 435 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.

TMDSCNCD28379D: TMDSCNCD28379D ADC isolated ground

electrocc
Expert 2450 points
Part Number: TMDSCNCD28379D
Other Parts Discussed in Thread: C2000WARE

Hi,

I'm using the TMDSCNCD28379D. In the pdf file "F2837x_180controlCARD_R1_3_SCH_02Oct2015.pdf" found in "C:\ti\c2000\C2000Ware_1_00_06_00\boards\controlCARDs\TMDSCNCD28379D\R1_3", on page 4 it's written :

"If desired, isolate (or semi-isolate) all GND nets on this page (GNDA) from the main GND. If done, the GND terminal of C82 should also go to GNDA.".

But how must we proceed to isolate GNDA to GND? Is there a switch or one other thing? Because for me when I test the ground with a multimeter, there is only one ground signal and it is GND.

Thank you.

Regards,

  • 0
    TI__Guru 60865 points
    HI electrocc,

    Very briefly, you would split the grounds into separate planes in the PCB, ensure that absolutely no signals cross the splits, and then join the two planes at a single point (usually on the back-side of the board directly under the center of the device). You can make the connection with either a 0-ohm resistor or an inductive bead.
  • 0 in reply to Devin Cottier
    Expert 2450 points

    HI Devin,

    And thank you very much for your answer.

    Ok, I understood, but my question is : how can I split (easily)  the ground in the PCB? Is there a resistor 0 Ohm resistor to remove or something else?

    Because for me, there's only one ground, and it is GND.

    Thank you.

    Regards,

  • 0 in reply to electrocc
    TI__Guru 60865 points

    HI electrocc,

    You can't separate the grounds on the ControlCard; the PCB wasn't designed with separate grounds.  

    The comment in question is targeted towards someone using the ControlCard schematics as a starting point for their own customer PCB.  I'll see if I can get the documentation updated to be more clear in this regard.  

  • 0 in reply to Devin Cottier
    Expert 2450 points

    Hi Devin,

    Ok, now it's clear for me. I didn't understand how we could separate the ground on the ControlCard.

    Thank you.