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Altera_Forum's avatar
Altera_Forum
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13 years ago

MAX II CPLD output impedance

Hello all,

We need to add an RC filter to certain outputs on our CPLD due

to noise on our board, thus we need to know for impedance matching,

what is the default output impedance for the MAX II CPLD's ?

I have looked through pretty much all the application notes I know of including the device handbook and the AN 248 with no luck.

Thanks a bunch in advance !!

Cheers,

Eric

1 Reply

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

    Did you notice figure 5–1 output drive characteristics? It tells you everyhing about output impedance, just determine the slope in V/I characteristic.

    I read about 30 ohm for 3.3V and low drive strength from the diagram.