Galvanic isolation, generally referred to as isolation, is a means of preventing DC and unwanted AC currents and avoiding a direct conduction path between two sections of a system. Isolation performs these actions while still allowing signal transfer, power transfer, or both, between those two sections. Semiconductor devices that offer galvanic isolation are referred to as isolators. Optocouplers are one of the first isolators to be introduced in the semiconductor industry and have dominated the industry for several decades as an exclusive isolation technology.

With semiconductor technological advances in the last couple decades, there are many other isolation technologies, like capacitive and magnetic isolation, that offer similar functionality as optocouplers with better overall performance. Among the competing technologies, TI’s silicon dioxide (SiO₂)-based digital isolation technology offers best-in-class performance, especially on high voltage rating, electrical characteristics, switching characteristics, and reliability. This white paper compares TI digital isolators to some of the commonly-available optocouplers with respect to various performance parameters. To compare TI digital isolators to optocouplers in standard interface circuits, see the How to Replace Optocouplers with Digital Isolators in Standard Interface Circuits application brief. When looking for a reliable and robust upgrade to optocoupler designs, consider TI's pin-to-pin opto-emulator products.