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ANBARASU's avatar
ANBARASU
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11 months ago

CYCLONE V FPGA POWER-UP SEQUENCE

Currently i am using the below cyclone V FPGA for my design,

Part: 5CGTFD7D5F27I7N

As per the CV-52001 (2023.10.18) -Volume 1: Device Interfaces and Integration

The recommended power-up sequence given as below,

Here Group -1 to be powered up first then followed Group 2

In group -2 is there any specific order to be followed?

1) Query: eg. VCCPGM should first then followed by VCCIO then VCCPD?

As per the table 10-1 , point 33 is not clear for me, can anyone help to provide more details.

In my case i am using VCCIO as 3.3V ,1.35V,2.5V and VCCPD as 3.3V,2.5V & VCCPGM as 3.3V,

2) Query: Bank 3B/4A and Bank 7A/8A uses VCCIO as 1.35V and VCCPD as +2.5V,

So can i enable the 3.3V first on group 2 and followed by 2.5V and 1.35V, Is this sequence is acceptable?

Regards,

Anbarasu S

Board Debug

10 Replies

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    11 months ago

    Hello,


    You need to make sure all the power rails in Group 1 ramped up to their own voltages first, then you can ramp the other power rails in Group 2.


    Within Group 2, there is no sequence, you may ramp up VCCPGM first then VCCIO etc , as long as you already completed all Group 1 ramp up.


    Notes : each power supplies must be ramped up within the given tRAMP time, which is <100ms for standard POR and <4ms for fast POR. Difference between Standard POR and Fast POR is the POR delay timing(this is not controlled by users). Users can only set in MSEL.


    regards,

    Farabi



    • ANBARASU's avatar
      ANBARASU
      Icon for New Contributor rankNew Contributor
      11 months ago

      Hi Farbi,

      As above mentioned, there is no sequence order required in group 2, But i could see the below statement.

      Here i am using Bank 3B/4A and Bank 7A/8A uses VCCIO as 1.35V and VCCPD as +2.5V.

      These 2 bank voltages alone i am using VCCIO and VCCPD as different voltages, other bank voltages either 3.3V or +2.5V for both VCCIO and VCCPD are same.

      Query:

      If i understood correctly if i enable 3.3V first in the group 2 and followed by +2.5V/1.35V together i will meet the NOTE 35 point. Please confirm.

      • Farabi's avatar
        Farabi
        Icon for Regular Contributor rankRegular Contributor
        11 months ago

        Hello,

        Please make sure you follow this pin connection guideline, link : https://cdrdv2-public.intel.com/654351/pcg-01014.pdf

        1. If you have same VCCIO voltage with VCCPD, you may connect the power rail to the same voltage regulator and power up together.

        2. If you have VCCIO less than 2.5V, for eg. you connect VCCIO to 1.35V, VCCPD located in the same IO bank must be supplied by 2.5V. For this case, you need to power VCCPD 2.5V first, followed by VCCIO 1.35V to avoid current transient.

        Back to your question: "If i understood correctly if i enable 3.3V first in the group 2 and followed by +2.5V/1.35V together i will meet the NOTE 35 point. "

        <ANS> Yes, correct.

        regards,

        Farabi

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    11 months ago

    This is power sequence timing diagram:

    this is tRAMP you need to follow:

    regards,
    Farabi

    • ANBARASU's avatar
      ANBARASU
      Icon for New Contributor rankNew Contributor
      11 months ago

      Hi Farabi,

      Thanks for your response!

      Regarding the below query, to avoid VCCPD current transient i should follow above "power sequence timing diagram (Figure 183)". Please confirm.

      As per the table 10-1 , point 33 is not clear for me, can anyone help to provide more details.

      Regards,

      Anbarasu S

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    11 months ago

    Hello,

    Another thing you need to make sure, please make sure the power ramp up for all power rails are ramping up monotonously(meaning no plateau during the ramping up). If there is plateau during ramp up, the POR circuit will trigger the device into reset mode again and not complete the power up activity.

    regards,

    Farabi

  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    11 months ago

    Hello,


    The current transient of VCCPD meaning here is the sudden inrush current happening to the VCCPD and from voltage perspective, you will observe a voltage spike(likely a voltage ripple) if you dont follow the power up sequence. If this voltage spike shoot up above the maximum limit of the allowable operating condition of the VCCPD voltage, the POR circuitry will put the device back to reset mode and re-run the power cycle again. This process will be continuous until the voltage satisfied all the operating parameters defined in datasheet. It is important to power up all the power rails in Group 1 first, followed by Group 2 to avoid this kind of failure.


    The maximum current transient will be ~1000mA for at least 50us will happen if you dont follow the power up sequence. You may need to add decoupling capacitors to smoothen the current transient if you dont follow the power up sequence. So to avoid this, it is recommended to follow the power up sequence as mention in user guide.


    regards,

    Farabi


  • Farabi's avatar
    Farabi
    Icon for Regular Contributor rankRegular Contributor
    11 months ago

    Hello,


    Ok, you may ramp up together VCCPD=2.5V and VCCIO=1.35V. Otherwise, VCCPD need to ramp up first then VCCIO. Both ways will make the device power up successfully.


    regards,

    Farabi


    • ANBARASU's avatar
      ANBARASU
      Icon for New Contributor rankNew Contributor
      11 months ago

      Hi Farabi,

      Thanks ! I got all queries resolved. Summary,

      1) VCCPD Current transient:

      Feedback:

      It is important to power up all the power rails in Group 1 first, followed by Group 2 to avoid this kind of failure.

      The maximum current transient will be ~1000mA for at least 50us will happen if you dont follow the power up sequence. You may need to add decoupling capacitors to smoothen the current transient if you dont follow the power up sequence. So to avoid this, it is recommended to follow the power up sequence as mention in user guide.

      2) VCCPD and VCCIO different voltage at same bank

      Feedback:

      Ok, you may ramp up together VCCPD=2.5V and VCCIO=1.35V. Otherwise, VCCPD need to ramp up first then VCCIO. Both ways will make the device power up successfully.