Hi. I've read some articles about surge input protection; I think it was regarding switches. Basically, they had a diode's anode connected to the input terminal and the cathode connected to the voltage source. It looks like this:
My question is that most diode datasheets that I've seen shows the minimum forward voltage drop as somewhere around 700mV. Another article that I read (I think this is about opamps this time), mentioned that the input is capable of handling a maximum signal amplitude that is VCC
In this situation, does that mean that I would need a diode with a lower forward voltage drop?
Also, I seem to be confused as to how this type of diode protection scheme works. Using the picture link, if the signal is higher than the VCC voltage by an amount greater than the diode forward voltage, then the diode conducts. So that would mean that the input is now at VCC voltage levels? If so, then wouldn't the diode "open" up again since the anode is now at the same voltage level as VCC?