Fundamentals of Integrated Transformers: From Principles to Applications

Magnetic transformers are conventionally used for distributing and converting electrical energy and managing high electrical powers. They are typically large and bulky, such that one may wonder whether they can go along with integrated circuits at all. However, their use in integrated circuits is absolutely ubiquitous [1]-[13]. They are used to implement fully integrated power amplifiers, frequency synthesizers, complete wireless transceivers, and power management circuits. They are indeed very useful, as they offer galvanic isolation to realize ac coupling while also allowing one to implement single-ended to differential conversion and signal or power combining.