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Altera_Forum
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8 years ago

Cyclone 5 mismatch between VCCPD and VCCIO

We created a custom board that has 5CSEBA4U19 chip. The VCCPD pins for all banks have 3.3V but VCCIO is 2.5 on some banks. The datasheet clearly states that I must set VCCPD to 3.3V when VCCIO ...
Altera_Forum's avatar
Altera_Forum
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8 years ago

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Won't the FPGA bank that has 2.5V VCCIO and is connected to the 3.3V EPCS get damaged because of this supply mismatch?

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No. Refer to table 2 in the "cyclone v device datasheet (https://www.altera.com/content/dam/altera-www/global/en_us/pdfs/literature/hb/cyclone-v/cv_51002.pdf)". This specifies the maximum operating overshoot the device can sustain before damage occurs to the device. Note: nowhere in this table does it specify how any of the rails are powered - it's independent of that.

If you're happy to assemble a board I'd suggest you will be able to do a lot with it. So, it will not be wasted.

All that can be said about input/output voltages, pre-drive behaviour and drive strength is that your setup is not supported, therefore not documented. However, as I've already suggested, a lot, if not all, of your board should work.

Cheers,

Alex