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TMS320C6457 DSPs Hardware Design Guide - Power Supply Layout Recommendations

Ken Delmage
Prodigy 80 points
Other Parts Discussed in Thread: TMS320C6457

I am looking for some clarification on Section 5.4 Power Supply Layout Recommendations in the TMS320TC6484 and TMS320C6457 DSPs Hardware Design Guide (SPRAAV7B - October 2009).

The first paragraph states that "... the PCB should include separate power planes for core, I/O, and ground,  ...".

I need to know if the intent of this statement is that there must be separate power planes for each supply, and that each of these power planes be located on separate layers of the PCB?

  • 0
    Intellectual 290 points

    Hi Ken,

    Each of the DSP's core supplies {3.3, 1.8, 1.2, 1.1} and any filtered versions of those {PLLV1, PLLV2, VDDR18, VDDA11, VDDT11} generally need their own power planes.

    That doesn't mean that each needs it's own layer though. You can have several planes (essentially a copper pour) abutting on any given layer. The DSP's pin layout makes this possible as all the pins of a common supply are generally arranged in fairly contiguous groupings (but not always!).

    This may not be the "TI-approved" answer, but my board is designed this way and the DSP runs.

    - Craig

  • 0 in reply to Craig Neely
    Prodigy 80 points

    Craig,

    Thanks for your assessment, but I really need to hear this from a TI representative.

    We are trying to apply their guidelines, and they should know the intent of them.

    However, it is good to know that your board runs with multiple power planes on the same layer because I'm pretty sure that we will need to do the same sort of thing on our board.

    Ken