Cyclone 5 mismatch between VCCPD and VCCIO

Question

Hello,We have designed a custom board using the Cyclone V FPGA (part number: 5CEFA7U19I7N). In our design, VCCIO is correctly set to 2.5V, but due to a mistake, VCCPD for one bank is connected to 1.2V instead of 2.5V.I would like to ask the following:Will this cause malfunction or instability in the I/O behavior of the FPGA?Is the combination of VCCPD = 1.2V and VCCIO = 2.5V explicitly unsupported?Can we expect issues such as unreliable output drive, weak signaling, or complete I/O failure in that bank?Does this pose a critical risk to device reliability or lifetime?We also want to fix this issue via rework on the PCB:Since the FPGA is BGA, direct rework is very limited.Do you have any recommendation for modifying the VCCPD line to 2.5V?Would a solution such as an external jumper wire, track cut-and-redirect, or a series resistor be acceptable?Your guidance on this issue would be highly appreciated.Best regards,FZNB

aqidayman_altera · Answer

Hello FZNB,As I refer to the Cyclone V Datasheet, this is not a supported configuration. For banks using 2.5V VCCIO, VCCPD must also be 2.5V. There is no condition for VCCPD to be 1.2V. In the guideline also mentioned the VCCPD and VCCIO must be compatible. However, any wrong compatibility between VCCIO and VCCPD, we are not guarantee on the device reliability. I do not have details on the possible effect as this is out of specification conditions. Possible rework methods include cutting the PCB trace to the VCCPD pin(s) and wiring them to a 2.5V source (using a jumper wire or similar). After rework, please ensure all VCCPD pins for the bank are connected to 2.5V and have appropriate decoupling.Reference:https://www.intel.com/content/www/us/en/docs/programmable/683801/current/recommended-operating-conditions-38794.html#fntarg_4https://www.intel.com/content/www/us/en/docs/programmable/683375/current/guideline-ensure-compatible-vccio-and.htmlRegards,Aqid

aqidayman_altera · Answer

Hello,I wish to follow up with you, do you have any more concern or other questions on this?Regards,Aqid

aqidayman_altera · Answer

I hope the previous response was sufficient to help you proceed. As we do not receive any response from you on the previous question/reply/answer that we have provided. Please login to ‘https://supporttickets.intel.com/s/?language=en_US’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.

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Cyclone 5 mismatch between VCCPD and VCCIO

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