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Power Supply to multiple 66AK2H14 devices

Angad Shah
Prodigy 175 points
Other Parts Discussed in Thread: 66AK2H14

I am planning to use "66AK2H14BAAWA24" DSP+ARM Keystone II Processor for my design.

I have read through the Hardware design guide, the document has assumed single device when it comes to supply decoupling and Bulk capacitor planning.
I need more clarity on how the power must be distributed to multiple device when a single regulator powers' multiple K-II device (Probably 5 devices).

Thanks in Advance.

Regards,

Angad Shah

  • 0
    TI__Guru* 81335 points

    Angad Shah,

    Welcome to the TI Keystone forum. I hope you will find many good answers here and in the TI.com documents and in the TI Wiki Pages (for processor issues). Be sure to search those for helpful information and to browse for the questions others may have asked on similar topics (e2e.ti.com). Please read all the links below my signature.

    We will get back to you on the above query shortly. Thank you for your patience.

  • 0 in reply to Raja
    TI__Mastermind 46460 points

    Angad Shah,

    Please see the attached presentation put together some time back by our power team.  It shows an optimized solution for powering multiple K2H devices on slide 10.

    Tom

    TI Analog Solutions for Keystone2 Family.pdf

  • 0 in reply to Tom Johnson 16214
    Prodigy 175 points

    Hi TOM,

    Thanks for the document. It was Indeed helpful in many aspects, But what I want to know is K2H Devices has Decaps and bulk that needs to be placed below/near to each device. If I have multiple device (5 or more) the output capacitance of the regulator needs to be taken note of.

    Below are my question:

    1. How many max devices each regulator will support

    2. In case where I have 5 or more devices, do I really need to place such high number of decaps and bulks for each processor (as the required number of decaps are nearly 400+)?

    Regards

    Angad

  • 0 in reply to Angad Shah
    TI__Mastermind 46460 points

    Angad,

    Most of the capacitors and other passives are related to the AVS CVDD core supply and the individual filtered supply inputs.  As you can see from the presentation, the AVS CVDD core supplies must be unique to each device.  Also, the individual filtered supply inputs cannot be combined.  You can get some gain with the IO supplies that are common across multiple devices on the board but this will not have an overall impact.  You need to put the recommended capacitors on the board for each device.  We recommend using small 0402 or even 0201 capacitors so that you can fit the required number of capacitors.

    Tom

  • 0
    TI__Mastermind 42545 points

    Hi Angad,

    Each K2 device will require its own SmartReflex core power supply for CVDD so that portion of the hardware design guide can be followed without variation. Power supplies for CVDD1, DVDD18 and DVDD15 can be shared across multiple devices but you will need to do a PDN analysis to ensure that each device will regulate the voltage properly for each supply. Since this is highly dependent on the PCB layout and placement of the components, we can't provide additional details on the number of capacitors needed for each of these rail. 

    Regards,

    Bill

  • 0 in reply to Bill Taboada
    Prodigy 175 points
    Hi Bill and Tom,

    Thanks for the response I have some clarity now.
    If you could suggest which Tool can be used for PDN Analysis

    Also, it will be helpful if there is any Design document or Development Boards that can be referred for multiple K2 devices on single board.
    I know that EVM by Advantech are available, but they all are for single processors.

    Regards,
    Angad Shah
  • 0 in reply to Tom Johnson 16214
    Prodigy 175 points
    Hi Tom,

    This document has resolved most of my quires. I want to know based on which Board this presentation was done for? Please can you share some design document or reference document for the attached design.

    Regards
    Angad Shah
  • 0 in reply to Angad Shah
    TI__Mastermind 46460 points

    Angad, 

    We have multiple customers that have implemented board designs containing more than one 66AK2H14 device.  The block diagrams provided show the power supply solution recommended to one of those customers who designed a board with 4 of them.  It was a successful and robust design.

    PDN analysis must be based on PCB extractions using true 3D simulation tools.  Since this is not available to most customers, our recommendations are limited to listing decoupling capacitors and a reference design as the EVM.

    Tom