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AThai8's avatar
AThai8
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5 years ago

What would happen if VCCPD is less than VCCIO?

Hi, I am using the Cyclone V GT. What would happen if my VCCPD is 2.5V and VCCIO is 3.3V for the same bank?

3 Replies

  • YuanLi_S_Intel's avatar
    YuanLi_S_Intel
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi AN Thai,

    There is no problem as both power rail are different. Supplying different VCCPD and VCCIO is depending on the I/O standard that you are going to use. You may refer to device user guide for more information about it.

    Thank You.

    • AThai8's avatar
      AThai8
      Icon for New Contributor rankNew Contributor
      5 years ago

      Hi,

      Thank you for the response.

      Please allow me to elaborate a bit further. Based on the data sheet VCCPD must be 3.3V when VCCIO is 3.3V and must be 2.5V when VCCIO is less than or equal to 2.5V. I have an adjustable VCCIO between 1.2V and 3.3V, my question is as my VCCIO varies, can VCCPD stays at 2.5V? Or should I switch VCCPD between 2.5V and 3.3V as VCCIO changes?

      Thank you.

  • YuanLi_S_Intel's avatar
    YuanLi_S_Intel
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi AN Thai,

    First of all, the VCCIO shouldnt be changing. It must be fixed at all the time. Thus, it is not appropriate for the method.

    Thank You