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Altera_Forum's avatar
Altera_Forum
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14 years ago

device size disproportional number of user IO pins

Hi, I have a question related to the number of user I/O for a the Cyclone IV E family for example, ....but I believe this issue may be common to other devices as well... Looking at the tab...
Altera_Forum's avatar
Altera_Forum
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14 years ago

You mean within the same package? I believe in the smaller packages, there are probably more than enough I/O on the die, but only so many on the package. As the die gets larger, more VCC/GND connections are needed, which are added at the expense of user I/O. In the largest package(780) you see the I/O count get smaller and then larger again. I'm guessing this package isn't limited by the number of I/O on the package for the smaller devices but the number of I/O on the die, but that's just a guess.