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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

    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.

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

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

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    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.

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