Is it allowed to have +-30V at the input, if the part is not powered.
The AD822 cannot have +30V or -30V applied to either input when there is no
power on the supply pins. As a general rule, the absolute maximum current into
a pin should be limited to 5mA for a short time. Some kind of external
over-voltage-protection would need to be added to the board in order to protect
the inputs (for example, a series current-limiting resistor).
Reference to Rev I of the AD822: Input Voltage = ((V+) + 0.2 V) to ((V−) − 20 V)
Important is the current limitation to 5mA
The engineer may want to consider our products that have over-voltage
protection designed into them, like the ADA4096-2 (see absolute maximum ratings
of the AD4096-2)