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Altera_Forum's avatar
Altera_Forum
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16 years ago

Power pin connection for Cyclone III

Hi:

I am using Cyclone III EP3C25E144I7N and only banks 1, 5, and 6. I was wondering for the VCCIO pins, do I need to connect all VCCIOs to the 3.3V power supply or I just need to connect VCCIO1, VCCIO5 and VCCIO6. Also, the Cyclone® III Device Family Pin Connection Guidelines say that all VCCINTs should be connected to 1.2V. I was wondering if I could only connect those VCCIOs of the banks that I used.

2 Replies

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

    The device handbook tells, that all supply pins in which configuration or JTAG pins resides, are monitored by POR circuit. Also:

    --- Quote Start ---

    VCCIO for all I/O banks should be powered-up during device operation. All VCCA pins must be powered to 2.5-V (even when PLLs are not used), and must be powered-up and powered-down at the same time. VCCD_PLL must always be connected to VCCINT through a decoupling capacitor and ferrite bead.

    --- Quote End ---

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

    I believe that JTAG or configuration pins are in only 1 or 2 banks. So if I power the VCCIO and VCCINT pins for those banks, would it be able to pass the POR state? I don't want to connect all the VCCIOs if necessary because I have limited space in my layout.