We have a voltage controlled current source with <0.5% error. We'd like to drive it with a voltage DAC, but the offsets are on the order of 0.5mV, which causes ~5% error in our current source. I don't see any DACs that have offset <50uV. Can you suggest a solution? Why aren't there any DACs that autozero like op-amps? At this point the only thing I can think is to calibrate using an ADC (force/sense). Another idea I had was to use a high voltage output DAC and attenuate (also attenuating the offset), as we only need 0-2V output.
I was also thinking to use the DAC8750 as the current source, but its accuracy is specified in TUE of full scale, which still seems too high, 0.2% of 20mA = 100uA. We need ~1uA accuracy.