I'm using an MCP3304, which reads 0-5V, to read 0-10V via a voltage divider. But I'm worried that a voltage spike could damage the IC. I'm hesistant to add a zener, because it'll affect the input.
I've read that the Atmega has overvoltage protection clamps, capable of sinking up to 1mA. Is this generally applicable to ICs as well? (e.g. is the ESD protection similar, e.g. high voltage at low current?)
I'm using a current sense opamp which has a VREF of 10V, thus should internally max out at 10V. However, I am multiplexing the VREF, and noticed that my voltmeter measured a ~12V spike (which could easily be more, but being averaged out on the display) when the multiplexer changed channels (Vcc=20V, channels 0V/5V/10V). Thus I worry that there could be a spike on the ADC signal the multiplexer changes input.
However, since the voltage divider is high impedance (10k from opamp output to ADC), and the ADC is, as I understand it, also high impedance, I wonder if this spike is even going to reach the ADC signal.
What would be the best practice? And the question: how well do ICs tolerate overvoltage at limited current? Or is the answer simply: they don't, but the high impedance causes them not to experience the overvoltage spike in the first place?