Does anyone know (1) how much transient current can be output from a pin and (2) how much (and how long) reverse current an output pin can take? For instance, consider the following circuit (driven by a series of 10 ms pulses at 5V):

  o----------------
       |          |
       = 10µF    1k LOAD
       |          |
  o----------------

which would be a classical filtered (smoothed) PWM circuit. When the pin goes to +5V, the capacitor would act like a short and allow very high current (assuming about 20 ohm impedance, maybe 250 mA) for a millisecond or so. Similarly, when the voltage drops to 0V, the charged capacitor will discharge, leading to a reverse current until it bleeds through the load. Will either of these damage the diodes in the pin or even the IC? Thanks. (Worse comes to worse, does this mean that a resistor and diode are needed to protect the pin?)