I have a field tech asking if he can connect 5V directly from Vcc to an
analog input on an 18F452. His purpose is to provide a 5V reference to the
input in an application board that normally allows outside circuitry to
control that A/D input. Fortunately (or unfortunately) there is a PCB
terminal arrangement with the A/D input straddled by a Vcc & Vss connection
that is  not being used.

My instinct is telling me that I would like to see a 5V zener to Vss and a
resistor to Vcc in case the voltage and/or current needs to be limited. For
him to get these parts in the field is a bit of a problem. I am sure it will
work without them, but just how safe is the input with only a hard-wired
connection to Vcc?

TIA,
Chris

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