5V tolerance and pull-ups
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‎2008-03-28 2:33 PM
Posted on March 28, 2008 at 22:33
5V tolerance and pull-ups
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‎2011-05-17 3:26 AM
Posted on May 17, 2011 at 12:26
hi,
say you have a 5V tolerant input that can be externally driven way up to 5V. then, is it safe to turn on the on-chip pull-up? no risk of current injection? thanks!Options
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‎2011-05-17 3:26 AM
Posted on May 17, 2011 at 12:26
from the datasheet (5.3.12):
''6. Pull-up and pull-down resistors are designed with a true resistance in series with a switchable PMOS/NMOS. This MOS/NMOS contribution to the series resistance is minimum (~10% order).'' seems like there might be current injection to VDD over the 30K~50K resistor, up to 0.1mA per pin @ 2V VDD.