I am busy designing a custom board based on Arduino's pro mini design.
In the official design, they have a MIC5205 voltage regulator supplying a constant 5V to the ATMEGA328 chip. However it is also possible to feed in 5V directly to the chip if you so wish, but when you do so, you are supplying 5V to the output of the MIC5205 chip.
In my design, I want to replace the MIC5205 chip with a LM7805 voltage regulator. But based on a bit of research it seems like you cannot supply 5V to the output of the LM780; based on a quick test, when you do so with 5V the chip doesn't seem to draw any current.
After going through each datasheet (MIC5205 and LM7805) I couldn't find any information about the chips' ability to withstand voltage applied to the output pins.
My question is finally:
Can the MIC5205 actually handle voltage applied to its output?
Is it bad to apply voltage to the output of the LM7805?
How can I tell from looking at the datasheet if a chip can handle voltage applied to its output?