Improved control system for process, voltage, and temperature compensation of CMOS active inductors

Abstract

Wireless communications play an increasingly large role in today's society. Today, many wireless functions are necessarily integrated into chips and other small packages to support miniaturized wireless devices such as cell phones, laptops, netbooks, etc. These Radio Frequency Integrated Circuits (RFICs) often require inductances to perform their function. Most RFICs utilize spiral inductors. Spiral inductors have their properties defined by their physical dimensions, often taking up large areas of IC real estate. There has been research into replacing these spiral inductors with active elements to reduce their size. However, these active inductors are based on parasitic elements that can vary significantly over temperature, supply voltage, and processing variations of the wafers themselves. This professional paper documents an improved control scheme to maintain correct active inductor behavior over process, voltage, and temperature variations in applications where the active inductor is used in a Wilkinson power divider.