Optocoupler technology has remained fundamentally unchanged since they became commercially viable in the 1970s. A Light Emitting Diode converts an input current to light which is detected by a photo-detector on the other side of an optically clear insulation barrier. Certainly over time there have been some improvements in performance, however, they have not been able to keep up with the demands of some of today’s high-speed data transmission requirements. Optocouplers tend to be slow with some of the fastest only being able to provide data rates up to a few tens of Mega-Hertz with propagation delays greater than 50 ns. To increase speed, higher input currents are needed. The LEDs used in optocouplers have a wear out mechanism whereby the LED’s light output becomes progressively dimmer which is accelerated by increased current in the LED and increased temperatures. This can limit the lifetime of optocouplers to less than 10 years in harsh industrial environments. Optocouplers tend to have a reputation of being very low-cost which is true for the lower performing varieties. However, for the faster or more integrated versions they tend to be more expensive and still inferior to fully integrated devices like ADI’s iCoupler digital isolators.