In order to do a precise current source of 1mA with the AD580, I need to know
the resistance to add between pin "output" and "V-".
According to the formula witch is given I=2.5/R+1mA, the resistance must be as
large as possible.
What is the resistance value that I must add to have 1mA of current ?
What is the limit resistance value that I can put for the use as a current
You should use slightly higher than 1 mA.
A 2.5Kohm resistor will give you a Current Source of 2mA.
For 1 mA , you will need a larger resistor , approx 5K, but this could
introduce noise, so you need to analyze the performance of your circuit with
respect to noise if you go higher.