Digital isolators

Silicon Labs is the inventor of capacitive digital isolators based on CMOS technology. This technology is becoming increasingly important compared to optoelectronic solutions, which have been established on the market for years.

Silicon dioxide (SiO2) is the primary insulation in Si8xxx products, Silicon Labs' Digital Insulation.

• Proven, well-controlled process
• Used in semiconductors for >30 years
• Compact; no requirement for thick SiO2 layers
• Very low defect density
• Dielectric strength: 500 V/µm (other dielectrics: 50 - 200 V/µm)

To ensure safety from electric shock, the insulation of an insulator must be able to withstand the voltages expected in the target application. The distance between the metal contacts on the outside of the component must be sufficient to prevent electrical conduction or "arcing" outside the device.

Creepage distance (Creepage) is the shortest distance along an insulating surface that an arc can travel (see figure at right).

Clearance is the shortest distance through air that an arc can travel (see figure at right).

Clearance requirements are specified in safety standards in terms of the minimum required "creepage" and "air" distances and are proven at Silicon Labs in the form of certificates.