The HCNR200/201 high'''linearity analog optocoupler consists of a high'''performance AlGaAs LED that illumi''' nates two closely matched photodiodes. The input pho''' todiode can be used to monitor, and therefore stabilize, the light output of the LED. As a result, the non'''linearity and drift characteristics of the LED can be virtually elimi''' nated. The output photodiode produces a photocur rent that is linearly related to the light output of the LED. The close matching of the photo'''diodes and advanced de''' sign of the package ensure the high linearity and stable gain characteristics of the opto coupler.