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What happens if VADIN > VREFH?

Question asked by zingere@apollo-security.com on Aug 14, 2018
Latest reply on Aug 15, 2018 by zingere@apollo-security.com

On the K60 datasheet it said VADIN should max out at VREF.

 

I have an analog input that can connect to different types of sensors external to the board. I want to have a reference voltage of 3.0V but also be able to clamp the analog input signal line to the 3.3V rail to not burn out the MCU pin in case of higher voltage being applied.

In my past experience with ADCs, if the analog signal went above the reference signal, it would just register as the max ADC value. Is that not the case here? Will having VADIN (3.3V) > VREFH(3.0V) cause damage? I don't know why any damage would happen to the pin if they are 3.3 or even 5V tolerant. The only issue i could think of is maybe reverse current flow somehow but I am not at all familiar with the internal circuity...

 

Also, what is the current draw of the VREFH? I cannot find it in the datasheet.

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