World’s Smallest Integrated Circuit (IC) Transformer

In the semiconductor industry, a transformer (or commonly called a balun) has traditionally been a standalone external component outside of the IC chip. By integrating the transformer into the IC chip, a manufacturer is able to save both space and production costs and pass on savings to consumers in the form of cheaper products.

With the rising trend of worldwide usage in communication devices and systems which require integrated circuit (IC) chips, the need to maintain high performance while reducing the physical size is an important distinguishing factor. Recognising this, researchers from the School of Electrical & Electronic Engineering have developed the NTU transformer believed to be the world’s smallest, using multi-layer metal overlap and mutual magnetic coupling enhancement techniques.

The balun has a broadband operation from 5-GHz to 6-GHz while another design covers an even wider operation band from 800-MHz to 2.5-GHz, which covers all the mobile and 2.45-GHz wireless applications including GSM900/1800, GPRS, CDMA, GPS, Bluetooth, WLAN and 3G/4G.

With the success of this invention, the team comprising Professors Do Manh Anh, Ma Jian-Guo, and Yeo Kiat Seng, is looking towards furthering this research to eventually create a “system-on-chip” which means that all the required electrical and electronic components are fitted into one single IC chip. The transformer design was fabricated and verified using Chartered Semiconductor's 0.18-micrometer RFCMOS process technology.