What is the max negative voltage the analog pins can take ?

Hello, I,ve looked into the atmega1280 datasheet, I got the arduino mega and I was wondering what is the max voltage it can take on the analog pins.

In the datasheet it says GND to VCC but it also says it is just a guideline.

As you can see in the picture it might need to take -8V. Vo is where I connect to an analogpin.

I just want to be sure because I cannot afford to burn it ;D

Thanks for reading guys,

arduino_input.JPG

Read the datasheet.

ATMEGA1280-16AU absolute maximum ratings: (1)Operating Temperature: -55 to +125?; (2)Storage Temperature: -65 to +150?; (3)Voltage on any Pin except RESET with respect to Ground:-0.5V to VCC+0.5V; (4)Voltage on RESET with respect to Ground: -0.5V to +13.0V; (5)Maximum Operating Voltage: 6.0V; (6)DC Current per I/O Pin: 40.0mA; (7)DC Current VCC and GND Pins: 200.0mA.

// Per.

If you apply -8V to your Arduino better order a new one first :)

According to the above excerpt -500mV is the max.

Maybe you should explain the purpose of the circuit.


Rob

In that circuit, the 100k resistor will safely protect the analog input pin of the Arduino as it limits the current to 80µA.

But as ever, it might be rather useful if you were to describe what it is you actually wish to do - the overall purpose, rather than the particular method you have dreamed up to do it.