Maximum voltage on PIC I/O line

[Rajinder]

Hi all
I wanted to ask what is the maximum negative and positive voltage i can apply to the PIC I/O line when configured as an input.
I think it is VDD + 0.3V and VSS-0.3V

The PIC has input protection diodes. So my question is can i go beyond these limits? Say i had 3.6V and -0.6V. Would the diodes not conduct and prevent damage to the PIC. I presume that there will also be a current limit of the diode that i cant exceed? I am using a PIC16F1938.

Thanks in advance

 

[Harald Kapp]

Would the diodes not conduct and prevent damage to the PIC

They will conduct and forward energy from the I/O pin to teh supply rail of the PIC with possibly desastrous side effects for the PIC.
The datasheet specifies a clamp current of 20 mA for this case. As long as your input current is limited to 20 mA or less, a slight overvoltage on the input pin will be tolerated by the chip.

Have a look at this thread.