What are the pros and cons of different types of galvanic isolations?

Galvanic isolation means the method to isolate systems electrically that operate within different potentials. There are various methods to accomplish this like optical-insulation, capacitive-insulation, magnetic-insulation, and mechanical-insulation. 
The table below shows the comparison among the insulation methods. Digital isolators have some weaknesses in the external magnetic field or CMTI. However, Toshiba supplies products with robust properties against external magnetic fields by utilizing a unique isolation transformer circuit.

  Photocoupler Digital isolator
Coupling Optical coupling Optical coupling Magnetic coupling Magnetic coupling Capacitive coupling Capacitive coupling
Pros Reliable Insulation
Multi-channel, High EMC
Long life, Fast-transmission rate,
Multi-channel, High-CMTI
Long life, Fast-transmission speed,
Cons Limitation of Transmission rate (50Mbps max) Weakness against external magnetic field* (EMC) Weakness of CMTI

* : Adopting our proprietary method to prevent noise from external magnetic field.

For Standard Digital Isolator products, please refer to the following links.

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