Galvanic isolation ensures data transfer without electrical connections that might create safety hazards otherwise. However, isolation does not come for free. The traditional optocoupler is easy to use but it is bulky, power-hungry and slow. Better performing optocouplers are expensive. What about digital isolators?
Digital isolators based on transformers and capacitors use magnetic and electric fields to couple data across isolation barriers where optocouplers use light. Digital isolators can be manufactured using CMOS technology allowing the integration of signal conditioning circuitry in the chip to greatly reduce power consumption and improve data transfer rates.
The iCoupler family from Analog Devices is a family of digital isolators that feature up to 16 kVpk surge protection and that can withstand voltages up to 5 kV. Signal speeds go up to 150 Mbit/s.
We tried one of those digital isolators in our Universal I²C Bus Isolator project that we will publish soon. Not only does this board provide galvanic isolation, it is also a level adapter. And it is not limited to I²C applications as it can handle all digital signals up to 1 Mbit/s. Of course it works great.