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FZNB's avatar
FZNB
Icon for New Contributor rankNew Contributor
6 months ago

Cyclone 5 mismatch between VCCPD and VCCIO

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...
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AqidAyman_Altera's avatar
AqidAyman_Altera
Icon for Regular Contributor rankRegular Contributor
6 months ago

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:

  1. https://www.intel.com/content/www/us/en/docs/programmable/683801/current/recommended-operating-conditions-38794.html#fntarg_4
  2. https://www.intel.com/content/www/us/en/docs/programmable/683375/current/guideline-ensure-compatible-vccio-and.html


Regards,

Aqid