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Altera_Forum's avatar
Altera_Forum
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12 years ago

how much current can EP2C5T144 drive to a load through its output pins???????

Your pdf files are so huge and filled with pedantic little details which I dont require, I cant even find the answer to this incredibly simple question and to be quite fair im very disappointed. This is such a simple question and I have spent over an hour looking at your pdf files for the cyclone 2 family unable to find this answer. Its just not right when you put in so many pointless details that you miss out simple information like this. I just need to know if i can directly drive an led 7 seg display or if I need to drive it with transistors. Thanks for wasting so much of my time.

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

    I'm not sure why you found the information so hard to find. Open the Cyclone II handbook

    http://www.altera.com/literature/lit-cyc2.jsp

    Look for the section "DC characteristics ... " in Section I, then turn a couple of pages. Table 5-7 on page 110 has the output currents.

    These are the output currents that Altera guarantees will also meet output logic levels. You can drive or sink a little more current for turning an LED on, but the output logic level might not be a valid TTL or CMOS level (which you would not care about when driving an LED).

    Table 5–1 on page 105, has Iout which is the absolute maximum pin current.

    If you're going to be driving a lot of LEDs, then I would recommend using a buffer, however, a few LEDs directly on the FPGA pins would be fine.

    Cheers,

    Dave