I know from datasheet of ADG201A-EP that the maximum OFF state leakage of this IC with power supply =+/-15V and VD = ±14 V, VS = ∓14 V is 100nA. This leakage is too much for the circuit that I am designing. But the input signal range in my application is much less that that is given in the datasheet. Power supply to this IC is +/-15V. The input signal range will be +/- 2V. I would like to know what will be the maximum OFF state leakage for this IC over the operating temperature range of -55C to 125C for this input range? Will there be a reduction from the datasheet values?
Good point. I just double checked here on the ADG1212-EP obsolescence. There is a pin for pin compatible replacement planned that will be a Pb-free version "SRUZ-EP-RL7". That will be a bit later in the year. So the ADG1212 may still be an option for you.
As alternatives. If you need a QUAD SPST. Here are two other options will low leakage that would be worth considering.
ADG613-EP (note this is a lower voltage switch)
I hope this helps.