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Altera_Forum's avatar
Altera_Forum
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15 years ago

Cyclone IV Decoupling

Hi All.

I have a Cyclon 4 FPGA (EP4CE22) and need to know the capacitors to use for decoupling.

I found and schematic example in Altera web page but is for Cyclon 4 GX and I am not sure it work in the same way.

Also I fount the Power Delivery Network Design Excel, that Altera gives you to find the capacitors to use, but I really didnt undesrand.

I am going to use a 40Mhz clock, and the power consumption is going to be this:

Iccint = 0.9A

Icca = 0.04 A

Iccd = 0.008 A

Iccio = 0.04 A

the most important I thing is the Iccint, so if anybody can help me to know how to do the decoupling it will be great.

Thank you very much.

2 Replies

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

    What package? Altera does a pretty good job at supplying app notes for decoupling. Have you looked around on the website?

    You are not running very fast at 40MHz. Are you planning on using any PLL's? On the BGA packages the VCCINT pins are typically all located in the center of the chip. Use 0402 package ceramic capacitors, something like a 0.01uF and 0.001uF (1000pf) pair for every couple of VCCINT pins or whatever you can reasonably pack in underneath the center of the FPGA should suffice for your needs.

    Throw a couple of 20uF bulk Tantalum caps outside near the perimeters of chip.

    Rob