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CG7's avatar
CG7
Icon for New Contributor rankNew Contributor
2 years ago

Cyclone IV shortcircuit in VCCint causes

Hi,

I've got a custom board with EP4CE6 on it, the board works but sometimes, it fails (defect seen on 6 boards).

The fail seems to happen at startup.

After inspection the power rail VCCint of the FPGA is in shortcircuit (less than 5 ohms).

I've checked the power supplies, there is no overshoot, the startup time is ensured and their rise is monotonous.

So my question is : what are can lead to this shortcut ?

- overvoltage ? if so what power rail can be involved ?

- cold sparing problem ?

- configuration problem ?

=> For me, there is a checksum in the bitstream preventing this to happen.

- can an overcurrent on an IO lead to VCCint shortcut ?

4 Replies

  • CG7's avatar
    CG7
    Icon for New Contributor rankNew Contributor
    2 years ago

    My design uses a high frequency clock.

    In some buggy cases, I suspect that the frequency of this clock may be way too high (maybe reach 1GHz), in this case, would it be possible that the FPGA core goes into short circuit ?

    The input is LVDS, is there a failure path between vccint and VCCA ?

  • AqidAyman_Altera's avatar
    AqidAyman_Altera
    Icon for Regular Contributor rankRegular Contributor
    2 years ago

    Hello,


    May I know what is failing during the startup? Can you elaborate more on this?

    If possible, you can also share if there is any snapshot on the relevant issue that might help.


    Thank you.


  • AqidAyman_Altera's avatar
    AqidAyman_Altera
    Icon for Regular Contributor rankRegular Contributor
    2 years ago

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