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Altera_Forum's avatar
Altera_Forum
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17 years ago

Power supply question for EP3C16 Device?

Currently I am using Cyclone III EP3C16. I will use 3.3V for all VCCIO, and 1.2V for VCCINT.

When I check the pin information for this device, I found that it is required that the supply (analog) voltage for PLLs uses 2.5V whether the PLLs are used or not.

It is kind of weired. I don't use PLLs at all. Although, it seems that I should create a 2.5V even I don't use it. Do anyone have any experience on this device? Do I must create 2.5V just for no use?

Thanks,

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    The 2.5V has to be connected, otherwise the device is hold in reset. A customer has used a silicon diode to generate an about 2.5V voltage from 3.3V, it alsways worked without problems. The good thing with Cyclone III is, that the PLL supply is less critical than with previous families, cause the analog PLL supply has internal voltage regulators powered from VCCA.