This section presents the design procedure for using the ISOM811x opto-emulators. External components must be selected to operate ISOM811x within the Recommended Operating Conditions. The following recommendations on component selection focus on the design of a typical feedback control loop for an isolated flyback converter.

When using an optocoupler in a feedback control loop for an isolated power supply, many variables can affect how to properly use the optocoupler, including the output voltage of the power supply and the type of controller the feedback signal is being sent to. For this example, assume that the output voltage of this power supply, V_OUT, is 5V, and the PWM controller being used has an integrated error amplifier with a COMP pin that acts as the output of this amplifier.