• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 145 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.

TMS570LC4357: Requirements on decoupling capacitors

vcvcvcvc
Prodigy 10 points

Part Number: TMS570LC4357
Other Parts Discussed in Thread: LAUNCHXL2-570LC43

Hello, I am currently designing a board with the TMS570LC4357. I've looked at the evaluation board and have seen the decoupling scheme used here. I have a few questions concerning this power scheme:

1) Are there any requirements other than 0.1uF per pin? I see that the evaluation board also uses a polarized 22uF capacitor followed by a 20mOhm resistor and another 22uF capacitor. Can these be removed? Or could this network be replaced with 1x 10uF? Or maybe a Pi filter with a ferrite bead?

2) is E1 necessary (NFM21PC474R1C3D)?

Thank you for your assistance.

  • +1
    TI__Mastermind 21111 points

    Hi,

    We don't have a lot of public collateral regarding design implementations but there is some discussion on this in the forums. For example, please refer to this thread which has very detailed recommendations for the decoupling capacitors

     RE: TMS570LC4357: Implementation rules for TMS570LC4357 

    Will echo the below recommendations as they are still appropriate in this circumstance

    1. add as many decoupling capacitors as space allows

    2. place the capacitors as close to the power pins as you can (you can place some underneath the MCU, and some at the edge of the MCU). 

    3. add 2 or more  bulk capacitors (Vcc, and Vio) as a low frequency noise filter and a charge storage device for the small decoupling capacitors.

    4. Since capacitor has ESL and ESR which reduce filtering effectiveness, so select the smallest surface mount capacitors.

    I think you referring to the HDK board but it is also possible to reference the LAUNCHXL2-570LC43 which also showcases the recommended decoupling capacitors.

    22uF + 20 ohm represent the bulk cap and filter. You can of course replace this with ferrite bead and 10uF for bulk capacitance

    Regards,

    Peter