Max voltage an Arduino digital input pin can survive

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1
  1. what is the max voltage an Arduino digital input pin can survive.
  2. i want the the value beyond which the corresponding pin will burn out.
  3. and at what input voltage value the arduino controller will consider it on and off.
2
  1. what is the max voltage an Arduino digital input pin can survive.

5V.

  1. i want the the value beyond which the corresponding pin will burn out.

5V.

  1. and at what input voltage value the arduino controller will consider it on and off.

The threshold for on is 60%, so 3V.

This assumes a 5V Arduino. For 3.3V models, the answers are 3.3V, 3.3V, and 1.98V.

3

Thanks... :slight_smile:

4

Supply voltage plus half a volt.

It's in the datasheet.

5

But the actual questions were not asking for the min/max values that were guaranteed to work but rather the values where things break.
Perhaps that was not the intent.

Answering the questions that were actually asked is more difficult since
you cannot use the data in the data sheet to determine the strict answer, since the min/max values in the data sheet are those that are guaranteed to work, and typically values outside of those values will still work.
However, values outside max/min values specified in the data sheet are not guaranteed to work and at some point can damage the part. Where that point it is can slightly vary between chips.

Determining the exact values asked for a particular chip in some cases is destructive (like #1 and #2) since getting the answer damages the chip.

--- bill

6

hassaan_128:

  1. what is the max voltage an Arduino digital input pin can survive.

  2. i want the the value beyond which the corresponding pin will burn out.

  3. and at what input voltage value the arduino controller will consider it on and off.

The 5volt and 5.5volt answers are not (always) correct.

It's ~0.5volt above VCC, and ~0.5volt below ground.
So when the Arduino happens to be off, it's +/- 0.5volt.
And for a 3.3volt Arduino it's +3.8volt and -0.5volt.

AFAIK the "switchpoints" of a digital input pin are stated as 30% and 60% of VCC.

A current limiting resistor can be used to prevent the pin from "burning out".
With e.g. a 100k resistor in series with the input (1mA), the pin will likely survive +/- 100volt.
I think it's wise, if a voltage divider is used, to dimension the top/hot resistor for <=1mA @max expected input voltage.
Leo..