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.

SM320F28335-HT: Bare die VSS pads around clock/osc pads

Part Number: SM320F28335-HT

Hello,

I am using the known good die version of the SM320F28335-HT DSP.  I have a question regarding the VSS pads numbered 148, 151, and 153 in the datasheet.  Are these pads connected internally on the chip, and is it possible to leave one or two of these disconnected.  If so, what are the drawbacks, and do you have any recommendations?

Thank you,

Brandon

  • Brandon,

    The official TI recommendation is to connect all of the provided pads (or pins) of a supply to a single net (preferably as a plane).

    Supply pads are typically allocated with the intent of distributing power evenly across the die, and will often share a single net on the die.  Leaving some of these disconnected may lead to voltage imbalances on the die.

    In special cases, supply pads may be strategically placed with the intent of shielding sensitive signals from external noise.  Leaving some of these disconnected may lead to an assortment of noise-related issues.  Based on the relative location of the indicated VSS pads to the clock pads, I would consider them to be of a shielding nature.

    -Tommy