I am considering to use Zener diode for over-voltage protection for a digital input pin.
The absolute maximum rating for the typical IC pin is given as from (GND-0.3V) to (VDD+0.3).
I can use Zener diode to limit voltage below VDD. However, the forward voltage of typical zener diode is 0.7V. which fails to limit low voltage to -0.3V.
My signal is 1MHz signal, and will It be safe to ignore since it is marginal difference and the duration is short?