The design of bandgap references for applications requiring minimal output noise
File(s)
Author(s)
Bowers, Derek Frederick
Type
Thesis
Abstract
The requirement for a low cost and compact voltage reference in modern electronic systems has been met in the last 45 years with several technological developments based on silicon integrated circuit technology. By far the most prevalent of these is the “bandgap” reference which generates a stable reference voltage by exploiting the characteristics of a semiconductor junction in forward bias. The big advantage of the bandgap reference is that it can be produced on virtually any integrated circuit process (CMOS or bipolar) with little or no modification to the process flow. The bandgap reference is also capable of operating from low supply voltages, down to below one volt. A major disadvantage is that available circuits generate considerable noise, often the limiting factor on accuracy in data acquisition systems of 16 bits and above. For low noise applications, the buried Zener reference is the most often used, and such references are commercially available from several manufacturers. Buried Zener references require considerable modification to standard integrated circuit technology, and are essentially incapable of operating at supply voltages below approximately 7 volts, from which they tend to draw significant supply current. The primary objective of this research work is to identify the major sources of noise in bandgap references and to provide methods of minimizing these components. A secondary (but very important) objective was to demonstrate that a bandgap reference can be designed which exhibits lower overall voltage noise than the buried Zener references currently in the marketplace. The research work concludes that different techniques are required in dealing with low- frequency and high-frequency noise, and that practical aspects such as die area and ease of application must be constantly kept in consideration if the improvements are to be commercially useful.
Version
Open Access
Date Awarded
2010
Advisor
Lee, Dr. Mike
Sponsor
Analog Devices
Publisher Department
Department of Electrical and Electronic Engineering
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)