QFor simplicity I wish to use a potential divider to attenuate the I/P signal,
using the I/P impendance of the AD536, and need to know if this is a constant
value, or changes with voltage, temperature etc.
AThe input resistance has huge ( worst case +/-20%) variation from part to part.
Having said that, the device is internally trimmed and the on chip resistors
have a fundamental temperature stability of approximately 50ppm/deg. In
addition, it shouldn't have any supply voltage dependency.
So you need a trimmable resistor to get accurate gain but once it is set it
shouldn't drift too much with T.