• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 424 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.

AWR2243: Which power rails and signals reference Analog ground (VSSA)?

Ltech
Intellectual 345 points
Part Number: AWR2243

I am trying to clarify, which power rails and signals reference Analog ground (VSSA) for layout and decoupling purposes?

Thanks,

Lauri

  • 0
    TI__Guru 58035 points

    Hello Lauri,

    all the 1.8V supplies and 1V supplies are referenced to VSSA. But we recommend using a single solid  ground on the board, ie shorting VSS and VSSA to solid gnd plans on the PCB.

    Regards,

    Vivek

  • 0 in reply to Vivek Dham
    Intellectual 345 points

    Dear Vivek,

    Here's a list of "Analog" rails and signals, I have compiled based on your comment and datasheet. Please correct, if I missed any below referencing VSSA:

    VIN_18BB, VIN_18VCO, VOUT_14APLL, VOUT_14SYNTH, VOUT_PA, VIN_13RF1, VIN_13RF2

    RX1-4, TX1-4, FM_CW_CLKOUT, FM_CW_SYNCOUT, FM_CW_SYNCIN1, FM_CW_SYNCIN2, CLKP, CLKM, OSC_CLKOUT.

    Thanks,

    Lauri

  • 0 in reply to Ltech
    TI__Guru 58035 points

    Hello Lauri,

    Also the XTAL pins are referenced to VSSA. But could you clarify your intent here? Are you planning to separate the VSS and VSSA on the board?

    Regards,

    Vivek

  • 0 in reply to Vivek Dham
    Intellectual 345 points

    Dear Vivek,

    I had the XTAL pins already listed. I'd need the list of rails and signals to be accurate as yes, I am planning to separate the references on the board. The VSS and VSSA will have the same DC potential.

    Thanks,

    Lauri

  • 0 in reply to Ltech
    TI__Guru 58035 points

    Hello Lauri,

    In these kind of complex mixed signal devices we do not recommend separating VSS and VSSA on board. We recommend having a strong gnd connection between the two and having a solid gnd plane. Its not easy to analyse all ground loops since signals will transition internally between analog and digital domains.

    regards,

    Vivek