INA129: Input Overdrive Question

Hi,

The safe input voltage of the INA129 is given as +/-40V.  Is this irrespective of gain setting?  Meaning, if I have +11V across the inputs with a gain of 50x, will the part be overstressed?  The supply voltages on the amplifier will be +/-15V, so the inputs will not go above the rails.

I am going to use this component as the front-end amplifier in a data acquisition system.  The input amplification will be either 1x or 50x (depending on the span of the input).  In the past, we have adjusted this gain by using an analog switch to apply a precision resistor across the gain pins of the amplifier.  I am thinking of approaching this differently, by having two parallel paths, one with a gain of 1x and the other with a gain of 50x.  The appropriate channel would then be selected by an analog MUX on the output. 

The reason for doing this is to minimize noise/tolerance issues on the gain pins of the amplifier due to the switch.  With this configuration the 50x amplifier would occasionally be overdriven by as much as 11V.  I've run experiments in our lab to show that the recovery time is about 4us when the overdriving input is brought back to 0V, which is close to the slew rate of 4V/us mentioned in the datasheet.  Is the recovery time dependant on temperature?  I only ran this test at ambient.

Thanks,

Matt