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280x GPIO Current Drive

Mike Mitchell
Expert 3395 points


I see in the datasheet that the internal pull-up/pull-downs on the GPIO pins of the 280x source or sink 100 micro amps.  And I saw the post on the forum by David Alter that says these are active circuits, not passive resistors.  I also see the datasheet spec that shows the input/output current of the pins is about 2 uA when the pulls are disabled.  Does one conclude from this that 100 micro amps is the most the pins can source/sink?  So, one can not drive an LED or something like from the GPIO?

  • TI__Expert 8500 points

    Mike,

    The 100uA is nominal. The spec for this is the Iil and Iih "Pin with pullup/down enabled" specs under section 6.3 Electrical Characteristics. For example, pins will pullups: the pullup for a given pin on a given device will be able to source between 80uA and 190uA. If you are looking for the most the pin is guaranteed to source, you need to use the 80uA spec. We guarantee the pullup can source at least 80uA. If you are looking for the maximum current that may be sourced by the pin, use the 190uA number. We guarantee the pullup will not source more than 190uA.

    Note this spec is different than the output buffer spec, which is either 4 or 8mA, depending on the pin. This is the current driven when the pin is configured as an output.

    Regards,
    Dave Foley