arduino - Is it safe to switch Vcc of Chip while IO still connected?

I'm planning to use an Arduino to control another chip by switching its power on and off using an N-Channel MOSFET, sort of like a SPI chip enable.

^{simulate this circuit – Schematic created using CircuitLab}

I'm just a little worried that doing this could damage the chip because there still might be (logic-level) voltages coming in on its IO pins.

Should I be worried about this or will it be safe to use this circuit to switch the power off to the chip?

Any other comments about this circuit? Should it work?

Answer

Probably not, unless specifically stated as such. One indication it isn't is a specification such as this one:

When Vcc is 0V, it is not recommended to have more than 0V at the inputs.

However, there are ways to isolate the chip you want to power down - for example using a voltage translator chip such as the 74LVC1T45 which is fully specified for leakage with one of the Vcc rails at 0V.

As well, you should use a P-channel MOSFET to switch the power. Low = ON.