There are basically three types of technologies for isolation; discrete transformers, optocouplers, and digital isolators. Discrete transformers are made up of a magnetic core material with two windings of wire that is used to pass electrical signals between two circuits through electromagnetic induction. Transformers are mostly used in power-supply applications, but they are also used as data isolators and inherently have good common-mode transient immunity. They tend to be bulky compared to other isolator technologies. Optocouplers are constructed with a pair of infrared die to form an optical signal path and encased by a high-voltage epoxy mold compound. Optocouplers also have high common-mode transient immunity and immunity to EMI, but have overall performance degradation and variation over time and temperature. Digital isolators in the market utilize three different technologies: capacitive, inductive, and giant magnetoresistance. A digital isolator based on a capacitive technology benefit from its immunity to EMI, low power consumption at high data rate, and low supply voltage range. Depending on the process and design, capacitive digital isolators may have higher power consumption for lower data rates. Digital isolators based on an inductive technology benefit from its high inherent common-mode transient immunity and low power consumption at low data rates. A downside would be low immunity to EMI relative to other digital isolator technologies. Digital isolators based on giant magneto-resistance have the benefit of large signal transfer without the need for internal amplification, but are susceptible to EMI and higher power consumption in general at all data rates.