Post Go back to editing

LT3085 as adjustable current source


I'm trying to use LT3085 as adjustable current source. From application note it seems to be very easy:

My design is as follows:

AD5272-100 is 100k Ohm resistor controlled through i2c interface.

I have two issues:

1. Output current is not adjustable. It means that current is not changing if I change resistance of AD5272 (for 0Ohm or 100kOhm output current is the same)

2. Changing load in range 2-100Ohm cause that voltage on output is keep stable (~2V) but current is changing so it does not work as current source but as voltage source

Could you please help me with understanding what is wrong here?