Shown here is a graph of different devices, both isolated and non-isolated, that address different levels of working voltages. Working voltage is defined by the potential difference between one system from another that is always present across the device. Sometimes isolators are used when isolation is not required. For applications where the ground plane difference between two different systems is known and less than or equal to 72V and only level translation is needed, then a high voltage ground level translator can be used like Analog Devices' MAX14842. For working voltages higher than 72V, isolation is handled by discrete data transformers, optocouplers, and digital isolators depending on the voltage level required. Discrete data transformers can handle up to 300V_DC of voltage difference between the primary and secondary windings, and rated up to 1500V_RMS of isolation for 60 seconds. Optocouplers can handle from 300V_DC to >600V_DC of working voltage, or an isolation voltage rating from 2.5kV_RMS to >5kV_RMS for 60 seconds. Optocouplers have been around for more than 30 years, but are being replaced with digital isolators due to improved performances in the areas of bandwidth, AC switching parameters, longevity, and lower power consumption. Digital isolators handle working voltage from 200VDC to 600VDC and are rated from 600VRMS to 5kVRMS of isolation voltage for 60 seconds.